If you have custody, then you have the say so. In Tennessee, there are no "grandparent" rights, much less greatgrandparent. As long as you are being a good parent, can pass a drug test (courts have been known to pop them), and can meet the medical, emotional and physical needs of your children, even if he lived with them for 14 years, your children are still your children and YOU HAVE THE SAY SO. IF they take you to court, there are local attorneys who will work on a sliding scale if income is the issue. Also, if income is the issue, there are so many community resources availiable to assist is all aspects. If you need specifics, contact me at ____@____.com and I'll be happy to help you out. Just remember the lasting effects it will have on your other children if they are feeling singled out. They know when someone doesn't love them as much, they just don't understand why.
Good Luck,
T.