Do I have a chance?

I just posted my story in adult and relationship group explaining me situation with my fiance right now so if you can read that great but long story short last night he got wasted at a work Christmas party and started screaming yelling hitting the car dashboard and threatening me that he is done if I bring him to his parents because he was doing all of this in front of our 5 month old son and scaring him so I dropped him off and he keeps saying he is done. My main question is... if I file for full custody as a stay at home mom do I have a chance? I take care of our son 24/7 when he gets home from work he goes and gets super baked and I end up taking care of both. I'm scared if I dont get 100% custody my son won't be taken care of properly because he is always high at home. Do i have a chance or do i stick it out and see if he changes? I dont want me family torn apart but him threatening me and doing all the things he did last night I'm not going to allow around my baby.