What color suit should the fathers wear?

Tan suits to match

No reason for them to match, either the groom or GM, or each other. Most of the night, they are their wives escorts. Light to medium grey, or navy, would be nice, but really whatever they want that is lighter and summery, not black or a dark brown or dark grey.

I’ve always loved navy with burgundy.

I would do the same as the groomsmen or navy. You don’t want a sea of colors in your photos