Trying to get the courage to leave him

So I’m in an extremely emotionally abusive relationship, looking back I should have saw all of the red flags but I guess I just kept brushing them off. A little back story he has a daughter from a previous relationship he talks down to that poor baby like she’s some stranger off of the street I dislike it his parents dislike it the only ppl who approve are his friends who also treat their kids that way bc they claim “it makes them hard you don’t want a soft kid” no talking to a 4 year old saying “shut the f@&$ up you stop acting like a little b&@$@“ is not okay and calling kids fa&&$@s for crying is insane. I am not okay with that mentality at all it’s sick. So it’s his daughter as well as me that he does this too and sadly I have a child with this monster the baby is now 7 months and he even talks to him that way every time my child starts to whine or cry he starts yelling at him and talking to him like he’s a piece of trash off the street or something saying things like “bro stop that sh&@“ “stop your fu&@$&g crying” “normal kids my friends kids they don’t do that crybaby a&@ weenie s&@t” like who on earth talks to a baby that way and of course I intervene when he talks to the kids like that and then he just blows up more. He says he’s gonna teach my son the streets and other stupid s&@t that will only make my child a stereotype and in jail. I want a future for my child. I’ve tried to talk and talk his parents told me in the very beginning after I was already pregnant though but they told me he was a horrible person and he will try to manipulate you and use the kids as pawns and tools and everything that they say has basically all happened. His daughters mom despises him and tried to make it to where he doesn’t get to be around their daugter I’m guessing he did the same stuff that he does with me with her as well I’m not sure but the judge gave them an agreement of 1 week at the moms 1 week at the dads. This is the reason I haven’t left I can’t leave my child for a week with that man by himself even when I go to the restroom I don’t put the vent on n I leave the door cracked so that I can listen for my baby bc he doesn’t have any type of patience or heart to deal with children or relationships, and I’ve walked in at least 3 different times now where my child was about to crawl off of the bed with his father literally on the same bed just careless not paying attention at all. I live in Texas if that matters does anybody know if it’s possible to get full custody of my son and keep his father away from him atleast until my child is much older. I just don’t want to take a chance by going to court and I don’t get a full custody type of thing and then my child has to suffer I couldn’t deal with that and neither should my child.