Custody and Visitation Issues: Child Custody of Three Teenage Boys to Live with Their Father in Florida

My question involves a child custody case from the State of: massachusettes. My fiancé was divorced in 2011. he lived in massachusettes at the time. he has lived in florida for the past year. his ex has custody of their three boys 16, 15, and 13. all the three of the boys since the divorce have wanted to live with their father. the oldest son was having issues with his mom because she is a johovas witness and he did not want to go to the kingdom hall. she had a lot of trouble controlling him. she tried to assign the court to take him into a program where if he doesn't conform to the rules of the house then the state steps in. at that time my ex was given temporary custody of the oldest son. he at the time did not want to move and leave his friends and girlfriend etc. she made a deal with him that he can do basically whatever he wants if he doesn't go and live with his dad. the second oldest is now having the biggest issue. he is gay. her religion is against this lifestyle and she makes it known to him. he is very depressed and wants to live with his dad.

my question is what are the first steps to have these kids live with their dad. can they just come and visit and not go back. or does everything have to be done in court. and how do you do this from out of state?

Custody and Visitation Issues: Child Custody of Three Teenage Boys to Live with Their Father in Florida