should we tell his mother are should i wait to have my baby first?

soooooooo this is quite a long story I'll try my best to dim it Down.

1: I've been with my boyfriend/fiance for 8 years now when I met him I was unaware he had a "kid".

2: "kid" basically when I met my boo he didn't clarify he had a son at the time was seven years old - further down the road it was brought to my attention the son could possibly not be his biological child (it's pretty obvious but who was I at the time to say anything about it) when I say brought to my attention I mean his whole family made it known to me they told him to get a DNA test an that the childs mother did her thing blah blah we know how that goes.

3: I'm currently pregnant with his daughter an only my side an his father knows about it. these are the main points to the whole situation . Now my man's mother is one of those go over your head type woman say one thing does another types. his *sons* mother took him from us when she got sick of me taking care of her son I suppose. now she's in jail for fighting her current boyfriend for trying to leave her she has 4 other children which she left in her boyfriend's hands (they've only known each other for 6 months ) honestly worst parenting I've ever heard of I would have personally left my kids with there grandmother are bio father's instead of this guy? but that's a story for another day . sooo the since my boyfriend's mother is in everyone's business she was around just in time to be there for the situation an her going to jail,she offered to take *son* which she did an brought back home I don't have an issue with this but the main problem was she didn't call my boyfriend are I an tell us the situation instead she decides to pretend to be the kids mom an order my husband around saying he needs to do this an that are this are that will happen?? school,ssi, etc things of that sort now I understand you talking to someone about what steps to take next but demanding my husband makes this move an not know the whole story pisses me off because whatever happens falls on him legally. she's let's him leave the house when he wants an he doesn't come home till after dark ?? he came home after school an she told him he could leave once again without asking the parents an guess what he came back with a fractured wrist we told her to take him to the hospital because no one gave her permission to tell him to do anything she threw a fit an said she couldn't because she gets off work an can't be bothered with the waiting etc ? like bitch did you miss the whole point stop giving permission when it's not ran by anyone. she also decided not to tell us that she gave his Aunte permission to come an take him on a picnic turns out they didn't plan to take him back home at all because the mom decided from jail she wants *son* to be with 6 month old boyfriend? my husband an I had to get police involved an everything just to get *son* back home ? I told Grandma she needs to be a grandma an stop overstepping boundaries Bec it backfires on my husband she said I'm the step mom an that doesn't mean anything (I'm personally not an agumentive type person if your irrational I just give up on it ) she got all upset an saying she's not the problem all the things he does he would do regardless, I said how if he is doing bad in school I wouldn't give him a cell phone if he is failing an lying I wouldn't Grant him privileges to go play with friends an hangout when he wants when he steals your CC card an lies about it I wouldn't give him a video game ? ( NOTE *son* did not act this out of hand when he lived with us he was well mannered and responsible lack of home training when the birth mom took him has made him this way he is now 13) but you get my point she goes over my husband's head trying to be *son's* mother are best friend when you need to be an authority figure she belitte me by telling me im the step mom an I shouldn't get involved mind you I've been with my man for 8 years now an currently pregnant with his official 1st child? but ok grandma I told her that's disgusting to say because we plan to move to Cali soon an what do you think will happen then you won't be in the loop like you like so much ? *Silence* she's even basically befriended the birth moms boyfriend treating him as if he is the kid's father seriously when *son* does something bad she calls the boyfriend an tells him so he just yells over the phone ?? before I knew I was pregnant my husband an i was outside having a cute time an I told him one day we're going to start our family she overheard an said " oh so that's the plan to dash away*son*!!! I was completely offended because what does we having a child have to with him dashing away someone? we've been together a long time it's due sooner are later then it came to my mind that maybe she just wants that link between my husband an the ex to always be there? I'm not sure my family told me to ask why he doesn't get full custody I said at first I understand the birth mom isn't exactly a civil minded person an he made it clear he doesn't mind taking *son* but he won't go back an forth with her which has happened alot during our relationship because she wants him back blah blah useing the child as a paycheck blah blah .my family also asked me to take him to get a DNA an fix it once an for all but I feel like that's pointless as well they've been around each other for years now finding out something I think he knows already won't change how he felt as he's always taken care of em .when I say he knows I mean he knows when we first got together an his family told me about the situation I got a DNA test via DDC it said 0.0000 I told him an he seemed to be hurt so I balled it up an threw it away when I got him off child support(*son* lived with us but husband was paying child support?) he asked me to schedule another DNA test at labreadynow, the morning of he said nevermind ? when I had my sonogram he told me before we went in he knew that he could only make girls *boom* we find out it's a girl an the doctor said men are in charge if creating the sex of the baby so maybe he has a feeling in the back of his head but doesn't wanna admit to it. Although I understand my family's Request I'm not sure if I should presue forcing him to get full custody of a child he basically volunteered to take care of an now he can't do anything ? an his mother is the devil I feel like if she find out I'm pregnant now she'll wish my baby harm because now this will interfere with her running my husband's life an taking control of the kid(when I say devil I don't mean it losly her an my husband got into an argument over my dog an the next day doggy got hit by a car) she has ways about her where if you come in the way if her an her son's she does wish bad on you she hated me when we first got together an I moved him out she blew up his phone an asked him to come over all the time to do house work when she has a whole husband herself ???? I need help should I tell her I'm pregnant an risk my daughter's health should I Force my husband to get full custody because in the long run we know he will treat my daughter differently (*son* has no simularties not that looks mean anything but I mean Noo simularites looks behavior nothing from the sono my daughter looks just like him an I know he thinks about it because he literally keeps saying it her nose her nose her head an all smiles ) I just don't know how to go about it I just want a healthy baby I don't want any drama I wanna be happy but I feel like me having her will make this whole situation more hectic from the ex "baby mom to the grandmother. we all know once the baby mom get weft I'm having a baby she's going to try an stir something up an I've already told you about the grandmother I need opinions help sorry this is so long but it's alot I tried to simplify.