is it possible to use my remote for my plane and connect it to my father in laws to help him fly or do i need to purchase a buddy box?

Lets start with some specifications. What type are the two radios?

Yes, it would help to know what brand and model of "remotes" we are talking about here.

Ken

yes it is but they have to be compatable and you need the correct buddy cord

If they are the same brand there should be no problem and in some cases even if not. Take both radios to the LHS so they can provide the proper cord. Remember the MASTER is the one that matches the Receiver and is held by the instructor.

If they are the same brand there should be no problem

Nope. Some Futabas are not compatible with other Futabas.

Dr.1