Are you sure you did the diagram correctly? Is your dad down a full rook? If it is correct you should have a clear path to victory. You should constantly simplify (get material off the board) to make the most of your material advantage. Eventually your extra rook will be crushing.
Your dad's position is full of problems. Dad has attempted an attack but with just a N and B -- it isn't enough to get the job done and those pieces, particularly the B, are vulnerable. His back rank is weak. His dark square bishop and his rook aren't doing anything.
If I were your dad I'd move Bf4 (hopefully I'm not missing something big): It double attacks (discovered attack on your B and attacks the pawn on c7) it lets the rook defend the back rank, and it activates the B and opens the way for the rook to enter the game. It also subtly defends the Bishop on h7. If you try to trap his Bishop with g6?? He plays Be5#!
After Bf4 you should probably just play Bd6 where your bishop and pawn defend each other and you forcing his Bishop to move again to avoid exchanging. After that you just want to bring your N and R into the game.
If your dad makes a dumb move, like Be4, you should move Re8 (which pins the bishop because you threaten Re1#).
You should probably resist the temptation for the moment to play f6 chasing away his N from defending the Bishop because it leads to complications you don't need after he replies Ne6. Get your N and your a-Rook involved and simplify whenever possible and you should win this game.
Well, the first thing you need to do is check to see what your, and your fathers pieces, are doing. Are all of your pieces reaching their full potential? Are there any weaknesses in your own camp that you can repair, or any weaknesses in your fathers position that you can strike at? You should seek guidance to get better at chess, not answers.