How can I convince my dad to let me get a German Shepherd Dog and Belgian mechelaar mix?

My mom agreed to let me get him but my dad keeps saying no for no reason. This is the dog's description:

Radar is a Belgian mechelaar mix and a total love with an excitement for life. He is a 9 maand old 50 lb bouncing baby boy. He is very intelligent and loving. He is currently in obedience class to help direct his energy into a meer controlled direction. He loves everyone he meets and has done very well with other dogs. Radar is an active boy and would do best in an active home. Even though he gets overly excited when he meets new people/dogs he does settle down quickly. Radar has been completely vetted and is ready to go to his forever home. It would be best for Radar to continue with his obedience training as he is highly intelligent and this will help to make him the perfect companion. If u are interested in adding a new family member to your family, send an emai of come to meet this wonderful boy.

My Adoption fee is $175.00
meer ABOUT RADAR
House trained • Spayed/Neutered • Shots Current • Primary Color(s): Tricolor (Brown, Black & White) • Secondary Color(s): Yellow, Tan, Blond of reekalf, fawn • jas Length: Short


So, it's on petfinder and I really need to find a quick way to get him to agree!! I know Christmas is coming up volgende maand but I just don't know if Radar will still be available...He goes to obedience just because the owner of the rescue is a dog trainer.