not pregnancy related but so disappointed in SO😔

This is going to be long sorry but I'd really appreciate your help.
My mom bought me a cheap little car that was 1500 last year. It was supposed to be for me so I could go to work and do my errands and to stop asking for her car. My SO had some problems and lost his car a little later, I sometimes let him use mine to help him out a little. Then he started needing it more and more to the point he just kept it. My mom said it was fine as long as he paid for all the expenses and kept the car clean and was responsible with it. Small things started going wrong with the car and he would tell me he'd get them fixed. To this day they are still unfixed- the speedometer doesn't work, the car doesn't count milage anymore, there's no radio, the entire middle part is loose, the driver door handle is about to come off, and the whole car smells like damn weed. I'm currently 38 weeks pregnant and my mom kept telling me to get the car back so I can use it for what it was intended for. But last night my SO was arrested yet again and the police towed the car. He calls me from jail and tells me to go to the police station and try to get his wallet back from them cause he had around 500$ so I could pay for the release of my car. Obviously they didn't let me have his wallet but they gave me release papers for the car since it's in my name and I'm 9 months pregnant. Turns out the release price for the tow is $400+. I don't have that. My mom said she could pay it as long as my SO paid her back as soon as he got out of jail Monday or Tuesday and I have to keep the car. This morning my SO calls again and I tell him the amount of money he has to pay my mom and he refuses! I cannot believe how selfish he's being, after all the help we've given him he expects us to pay and still keep the car. Then he tells me we can just keep the car because it's a cheap ass car and he's already found a way to get another one and he simply won't pay my mom the 400. I'm so mad I'm so disappointed and I don't know what to tell my mom. Please someone help me what can I say to her and my SO to convince him to pay her back? I don't work and my mom needs that money by this Tuesday urgently I'm crying 😣😣😣😣
UPDATE: I told my mom what my SO said and she still got the car out. You know what's funny? How every time I post about a problem I have with my SO or things that he does behind my back, always, people comment how I should leave him. Forget about him and move on. I would like to, but I simply can't bring myself to. The only way I'd be able to forget about him is if he moved away or I moved away and never having to see him again. But that would break my heart to a point where I wouldn't know how to go on, sometimes I feel like I love him more than I love myself. I know it's wrong to have those types of feelings for someone, but honestly I can't help it. Ever since we had our first problem very early in our relationship, everyone around me told me to forget about him. And I stuck with him. Now here I am 5 years later expecting a baby girl from him. I love her very much and it hurts so bad to think about her growing up without a father. He loves her but he doesn't know how to be good.
I've come to realize it.