MIL stole husbands tax return.

Enedice
Ok so I had asked in my previous post of anyone wanted to hear this story and got some replies! So here it is. 
It was last year in February and my husband and I (then fiancé) went to do our taxes. Everything went well, and we were each getting a pretty big refund which we were excited about because that money was going to help pay for the wedding/honeymoon. We get that all done and head home. The next day he gets a call from the IRS saying that he had committed fraud in his taxes and that his mother had already put him down as a dependent so his would be terminated and to expect another call later. I was furious. I had EVEN TOLD MY MIL the previous day that we were going to do our taxes tomorrow and I asked her to make sure she had not put him down as a dependent especially since he did not live with her and was roommates with my brother for that whole previous year and prior to that lived on campus in a different city. And he used to live with his dad as they are divorced.  She says "no I didn't put him with me and ok that's good that you guys are doing them" (liar!!!) so now I'm calling her and she won't answer. I go to her house, and confront her and she says that it's her money because she's his mother. I told her "he hasn't lived with you for two years and if anything he's been supporting you not you him! And he's lived with your ex husband since you got the divorce in 2013." I call our tax guy and he tells me that she's not allowed to put her son if she did not provide care or housing for him that year. He says "that's like her wanting to put him down even after your married simply because he's her son hahaha" so our tax guy calls us back after 2 days and says that there would be no consequence to my husband because he had solved everything and we could go and file a complaint so she could get a penalty and have my husbands tax return back. My lovely:horrible: husband refused to do anything and blamed me for making things worse! Two weeks went by and I kept bugging him to fix this because we needed that money for the venue. He kept saying no and that he wasn't going to do anything to his mom! I was 👌🏼 that close to calling off the wedding ladies!! He never wants to do anything against her but will always go against his dad! A whole month passes by and we have not contacted his mom at all and uninvited her and her family from the wedding. (Clearly my choice) I finally convince him to do something about it and he does but tells me it's so that I stop bitching. He convinces his mom to go to the irs and say it was a "mistake". Our tax guy goes too and they get everything solved so that she doesn't get a penalty. He gets his tax return in the mail and we go to cash it (this was in April already). I'm still not talking to her. My husband puts the money in our safe. Little did I know that my MIL knew the code to our safe and one time when she went to visit him while I was working she convinced him to giver her money for idk what! She goes to the safe and took our tax return envelope! I go visit him and my brother as we were going to have dinner and discover this. He tells me what happen and I just walk out and go back to my parents house. I didnt even argue. I just left.  I was that furious! My brother in law went to talk to her and he told me she said that it was her tax return too and that her son had given her money. (Pretty sure he didn't give her 2K) fast forward to July and he refused to ask her back for the money. She finally gives in and gives him 1.5k back in September. One month before our wedding because she's pissed she's not invited. I invite her back to the wedding but tell her that she will not be participating in anything and will be simply a guest. She says she can't believe we got like this over money. I tell her it's not just about the money. She has lost any trust I had for her and my respect that was already fading anyways.