I think they would love to help with a fundraiser! I have a neighbor who is a BC survivor and she is super excited about May and about having a fundraiser.
The only question that may come up would be whether you're going to donate any portion of your commission as well, which of course is up to you and you'll know whether your family is going to expect that or not. And you can explain to them that you don't get a full commission on fundraisers anyway.
Good luck!