If you are a minor you are not allowed to decide where to live, it's up to the judge if your parents can't decide. And clearly you can't live with your dad if he's in prison. If your mother gives up custody you can end up with a relative or in a foster home.
Yes
I would need to know more on the circumstances. Family services are a funny thing. Tell him to check Dads House below.
see links and Dads House
Unless specified in the court order, the husband or maternal grandparents. See Dads House Below
beer
As long as the parents are OK with this nothing happens. If it breaks the custody order though and the custodial parent did not agree to this, the police can come and take you back while the non-custodial parent can get into legal trouble for not sending you home.
If Mom has custody and Dad does not, then yes, she can.
There are rules for all adults who have custody of children, joint or otherwise, fathers or otherwise. To find the custody rules for your area of jurisdiction you will need to contact your local authorities. Any child welfare organization will be able to help you with contact details.
A motion is not a court order, and she can only get a temporary order of custody while in possession, unless she lied to the court. see Dads House below.
To get kicked in the Doo Dads!
Dads - 1986 The Thing on Allan's Nose 1-3 was released on: USA: 26 December 1986
Go for Bird Nest Custody. Learn how to prep for a custody challenge at Dads House. see links