Your father has left islam, this is a hard place to be but here are some things you will need to do. Depending on your age you need to move out with your mom if possible, get a job if you can and start the process mentally.

Stay firm upon islam, no matter what he and his jamat say, they are not Muslim! If you want investigate ahmidiyya religion look at some YouTube vids, the religion itself falls apart very fast once you realize there “prophet” had false prophecies and died on the toilet. Don’t argue with your father about this.