By petitioning the court with jurisdiction for a modification in the custody order, wait for the court hearing and then provide compelling evidence and documentation why it would be in the best interests of the child for the mother to have custody. I would strongly recommend you obtain the services of an attorney experienced in family law to assist you.
Only if she is unfit or willing. Otherwise the most he can get is shared custody.
yes
An 18-year-old can live wherever he or she chooses.
That depends on the custody order, but she can file for a change of custody.
Yes you can gain custody of her.
see links below
She can probably get her father to appeal for custody.
The mother already has sole custody. The father has not rights. see link
well by law, he is now a adult, so he can make his own decissions, but i do not think his father can no longer get custody because he is 18, but im not 100% sure
If he is legally the father he has a chance, of course. It's up to the judge. He has to petition the court for custody.
The chances for the father to claim custody of his 8 , eight year old child will be very hard as he is known to smoke pot, and under the influence of pot he is likely to harm the eight year old child. So the mother has a better chance of keeping custody.
If mother has custody, then she has all the say until the girl turns 18. If she objects, then the girl must obey.