If divorced already the father stop paying child support at 18she is 20 now is the father still responsible to pay support if she is going to college

This is a family law question. Without any further details, I can only give a very general answer: both parents and the child have responsibility to pay for a child's college. The amount of each person's responsibility depends on each person's ability to contribute. If the parties cannot agree, any one of them can take the matter to court and have a judge make the determination.