Custody question and child support questions?

In texas I just filed child support on the father of my sweet daughter. He is 23, doesnt work or have his own place, or even a stable place to live. I know that during out negotiation coming up, custody/ visitation will be established. Can anyone tell me why will happen? Will he have to see the baby(5 months) at his mothers since he hAs no stable home himself? He has a back ground of rehab, the pavilion, jail and drugs... What can I do?