Need advice on boyfriends mom

So, my boyfriends mom very obviously doesn’t care for me. She doesn’t make any negative comments towards me she just doesn’t really say anything to me at all. We’ve been dating almost a year and I met his parents pretty much immediately. I’ve never thought of myself as impolite and I’m on good standing with all of my friends families/other adults in my life etc. If my boyfriend and I walk into his parents house his dad will immediately look at me and we’ll say hello/ how are you but his mom will not even glance at me. The door we enter through is right by the kitchen where she typically is doing something. Say she’s cutting vegetables or doing the dishes... even if his dad is not in the room we will walk in and she will keep her back to us. So I will take off my shoes and wait until we get closer to her and we eventually make eye contact even for a brief second to say hello as I feel like it’s just awkward to say hello to the back of someone’s head from across the room. Even when I say hello she says it briefly and then looks away again. When I’ve been left sitting at the bar or something momentarily while he goes and does something I will attempt to make small talk with her but we really don’t know anything about each other for me to start a full blown conversation, but even when I do put in the effort to bring something up she will answer a few times but then stop talking and just say “mmhmm” or something. I’m a very friendly person but I’m not extremely outgoing so I don’t just talk and talk and talk when I feel like it’s a little awkward. But I’ve always been respectful in their home (taken my shoes off immediately, do not curse, don’t sit on my phone etc.) so even if I’m quiet I don’t foresee that as a reason to dislike me because I’m not rude about it. I’ve even always bought stuff for them to give to their dogs when I get my dogs stuff etc (we’ve pretty much only ever talked about animals lol.) Hind sight, my boyfriend has only had one girlfriend his entire life and it was only for a few months right out of high school 6+ years ago. Other than that he’s barely even talked to any other girls. I’ve had my own place for a while now so after 6 months of dating he started staying with me every single day he was home (he’s a truck driver so he’s only home Thursday or Friday nights through Sunday’s) but he’d still go see his family every day and we’d buy steaks and he’d cook them for everyone over there. He officially moved in with me a month ago. Mind you, she’s never invited us over for dinner. He’d have to ask if they want steaks for dinner and they’d say yes and give him a head count and he’d buy and pick them up and cook them over there and his mom would make a side or two that they wanted with them. Dinner’s are always extremely quiet minus the men joking here and there and she may say a few things here or there but most times she won’t speak at all. Dinner is mostly listening to forks hit plates which I’m not used to from growing up in a loud family. After my parents divorce my family hasn’t been close but before it was always very welcoming even to strangers. My boyfriend is EXTREMELY close with his family though so it’s very important that I am cool with them. His dad is super nice and so is his brother. Obviously I don’t just go hangout with them like I could his mom or sister if we were close though. His younger sister is very nice also but she’s rarely ever home so I haven’t been around her too much. Well with the holidays coming up I’ve been putting a lot of thought into what to get his mom for Christmas (I decided on a family photography session because I know she likes for them to get family pictures done and that’s something she can schedule when she wants to do it. My good friend is an AMAZING lifestyle photographer and I really think his mom would enjoy the pictures.) Well knowing that we aren’t that close and I’d like to kind of break the ice (we don’t even have each other’s phone numbers) she popped up on my Facebook suggested friends and I asked if he thought I should add her. He said yes, that’s a great idea so I did! Fast forward a few days and I checked her profile to see if it still said sent because I hadn’t gotten a notification and it only gave me the message option but we weren’t friends and I couldn’t add her again. I researched it a ton and he and I even made a Facebook account (we used my cats name lol) to test what would happen if we declined a request and we both got the same screen that I had on his moms profile on the fake Facebook profile. So we had proof that it was declined. We obviously weren’t close but I didn’t think she outright hated me enough to decline my friend request lol. So he asked her what happened and she said she didn’t know, that she’d gotten my request in her email only and didn’t deny it (yet didn’t confirm it) and doesn’t know what happened. He told her that I don’t have the option to add her again and that she’d have to add me and she said she’d try to figure out what happened but she was very vague about it and kept just saying that she didn’t know and changing the subject. We also knew based off of trying it with the fake account that even if she declined me she could still add me even if I couldn’t add her. Well it’s been a week and he’s asked her several times now what the deal is and she just keeps saying she doesn’t know. Now if she had very few Facebook friends I’d be like okay whatever, maybe she just doesn’t know me well enough (even though I’ve officially been living with her son a month but practically five months now.) But she’s friends on Facebook with his ex girlfriend from high school that he dated less time than me and that she also wasn’t close with, and she’s friends with a few of his old friends whom he doesn’t even hang out with anymore and who I know and have been told that they barely know her. So it’s not like she’s just extremely private. Not to mention, I screenshotted and sent him a picture of my sent request to her saying “done✅” and from that screenshot to when I found out she’d denied it we had another mutual friend that she’d added and not me. So like....what the heck?😂 I wish she’d at least just tell me why the heck she doesn’t like me so I could try to fix it, instead of being at a loss! Any tips?! With Thanksgiving and Christmas coming up I was hoping we could be closer and I could help her cook and it seem normal and not be awkward lol. I guess I just feel like if she can’t even accept a friend request on social media that speaks volumes and I didn’t even think we had any genuine issues other than just not really knowing each other that well yet.