His car seems more important than us...

Hi everyone this is my first post here and I am seriously soooo excited to be here. I've been reading a lot of people's posts and oh my can I relate! My hubby was diagnosed with ADHD as a child and now years later I think it still really affects him. We've been married for almost 2 years with a 10 month old  and I am so about ready to throw in the towel. One of the main issues is money and his stupid, STUPID car.. 2013 ford mustang decked out, that was a base model and he has pouuuuuured money into over and over when I have to use gift cards from our baby shower to pay for diapers and baby food! :( the other night I told him how we are going to start paying off all of  HIS  debt, about $20,000 total and I said that requires you to sell your car, so we can pay off the car loan, to which he said "fuck no" (excuse the language) but really. We are living with his grandparents because we can't afford anywhere to live and as soon as he gets paid he spends it on his car before I even have a chance to pay bills. I just feel my son and I are Sooo unimportant compared to that car, he says it's his baby, but really isn't you're infant son your baby?!! Idk what to do.. He obviously values that car so much over us that I can't take it anymore.