I think that as others have mentioned, you could wear navy, grey, dark purple, or dark brown. Even dark green would be good. Or wear some black and brighten it up with a colourful scarf or blouse. A scarf is good because as Callistemon suggests, you can pop it in your bag if you fee uncomfortable in it.
My husband has said he doesn’t want people wearing black at his funeral but I told him that if I’m still alive, I will be wearing black because it certainly won’t be a day to celebrate for me. And he won’t be there anyway.
A funeral isn’t for the dead, it’s for the living, and they have to do what they feel is appropriate.