To begin, I'm so sorry for your loss. ((hug))
If you are wearing a dark (especially black) suit, then the silver/gray and white tie would be fine. I've actually performed a couple funerals with that exact same outfit (Wal-mart ties ftw).
Dark colors (except in the situations Nygeel mentioned) are appropriate, but a completely black outfit is (usually) not. A white long-sleeved button-down shirt as part of the suit would be perfect.
If you own black dress shoes, then wear those - make sure you shine them first. Black shoes with a black suit. If the best pair of shoes you own is a pair of tennis shoes (or sneakers, depending on what you call them), then wear them. While it's not the best combination, you're family, so the rest of the family SHOULD understand. I've found folks to be a lot more understanding and appreciative at funerals. That wouldn't be the first time tennis shoes were worn with a suit. Just don't wear it to an interview.

Good luck!