Need help with my story!?

So I'm writing this story about a 17 year old guy who's mom died when he was 8 and hes having a hard time getting over it, unlike his family which causes him to not have much of a relationship with them. He doesn't really spend time with his sister (12 years old), brother (19 years old) and his dad, because he thinks they've forgotten his mom. He's from Canada, though they had to move from Montreal to Seattle because his mother's family blamed him for his mother's death, and his dad finally decided to move. He meets all these new people and basically does alot of cool stuff with them because of his new girlfriend, though what I'm stuck on is that I need him to go back to Canada for a few months with his brother, Father, and sister (he's starting to have a relationship with them)

I dont have any clue as to why though. I was thinking that maybe It could be because his Grandpa is dying and as his last wish he wants to get custody over his younger sister, so they have to go to court over it for 2 months but I really don't like that idea.

Any suggestions? Thanks :)