Custody advice!

Hi lady’s ... i would really like some advice if you’ve been through this yourself and how it all went down.

Sooo I’m thinking of separating with my sons father but every time i try to talk about it with him he threatens me with court. He tells me that he wants to have our son the same weeks he has his other son from a previous relationship which is every other week sun-sun. I’m sorry but is that even good for a child to be away from either parent that long?! I just can’t imagine. Another reason is i do not trust this man with my child alone.. he hardly takes care of his other child when he’s here and just yells and is frustrated the whole week. Smokes weed literally right next to him and i even have pictures to prove it. Doesn’t bathe him , doesn’t make or get him food... the poor kid wouldn’t eat or get properly taken care of if it wasn’t for me being there honestly. Just seeing all those things make me terrified if a judge decides MY son can stay in his care. Of course i want my son to be with his father but not that long. Am i wrong? .... what can i do ? Will the judge let him have him ?

ALSO for those who are going to say “we’ll why would you have a child with him in the first place etc” he was a good father in the begging then things changed. I tell him every time he needs to do better and all he does is yell in my face saying “i was a way better father before you came into our life” like blaming me for his actions. I just don’t get it. But I’m done , i don’t need my son seeing this bs