My 19-year-old sons ex doesn't want her to have anything to do with his baby: Advice?

So I need advice my son is 19yrs old his ex just got ahold of him and said she’s pregnant. He tells her he’ll be there to help raise his kid and he’ll help her through the pregnancy as much as he can. Then she says she’s planning on going the single mother route and wants my son to have no part of the child’s life. Other than talking to a Lawyer and asking the court for a DNA test and upon the results of that a custody order is there anything we should do that were not thinking of? He is willing and able to help raise the child he works and can provide for the baby. He is mentally stable with no criminal record.