How can a dad get custody of his baby in Texas?

[Brooke]

So, my boyfriend just had a son in December but the mother of the baby will not let him in his life and she always messages him telling him how horrible the baby is and she put pictures of the baby laying on his stomach with a fluffy blanket under him in a laundry basket and a picture of him laying on the edge of the bed with a stuffed animal, both of which can easily suffocate him. She even called my daughter which is only 1 day younger than her son ugly. What kind of person calls a baby ugly? Anyway, my boyfriend never did anything wrong, in fact he has a job now and is working on trying to get his own place. But in Texas courts favor the mother and he can't get the pictures off her instagram, because she blocked him, to show court. So, how can he get custody of his son? He deserves him way more than a mom that doesn't even want him..