My daughters rights are going to be terminated. I as a grandparent live in another state. I tried to get the court to place them with me. That was unsuccessful because of living in another state. The children have been with a half cousin of my daughters. The have been with them since April. Do I have any rights to try during the termination hearing to gain custody of my grandchildren.

I would ask a lawyer who specializes in family law in the state where the children are.

Synnen is, a lawyer would be able to point you in the right direction.
In any of the situations I have been in, it took the seeking guardian to move where the children were living. That was when the children were already in school and they were 7 and 10. GOOD LUCK!