Hmm.. that’s a tough one. I’m really sorry to hear about your dad, by the way! It’s natural to go through a rut like this, believe me. Regardless of how you lose someone, your motivation can get shot for a long time. Heck, even mine is kinda non-existent at the moment. I haven’t really drawn anything in a long time.
The only thing I can tell you is to hang in there! It might take a while, but your motivation -will- come back. It might seem grim at the moment but you will get that spark eventually, maybe at the most random time. Do whatever makes you happy. Be with friends, listen to music, just anything to keep you positive. But most of all, -keep- drawing, even if it feels wrong. You don’t wanna get rusty. Even the smallest doodle, just keep going!