My question involves emancipation laws for the State of: Missouri

2 neighborhood boys came into my life thru my daughter 2 1/2 years ago.
One is 18, the other is 16 now. They lived with their mother and a 26 year old brother in a house that their uncle owns. The uncle pays all the bills for them and brings them food. The mother left them in Dec. to live in a one bedroom apartment. (She has some mental problems that she would never admit too.) The 16 year old still has to have some contact with his mother because she is the person who takes him to the doctor and such. How does he either emancipate himself or transfer his legal guardianship over to his brothers. She causes more problems than not and yet she doesn't pay for his upkeep, take care of him or anything. This young man was also home schooled his whole life and with her leaving it has left him with not having a teacher and afraid of public schools. He really needs help getting his guardianship changed over or whatever. Can anyone give us advice please?