My cousin's getting married there. She wants to know if it's fine to dress casual for a courthouse wedding. She said they'll be celebrating right away afterwards anyway. Is this ok?

I will be attending a Celebration of Life this weekend. However, it's at the country club instead of the church. So: 1. What to wear? 2. What to bring? 3. What to expect? It's from 5:30 to 8:30 PM. No formal invitations were sent or anything. The family is utterly overwhelmed by the unexpectedness of the tragedy. I've sent a message to my boss' fiancée, but no response yet. Although she did say I shouldn't feel obligated to go, but they've been to my kids' birthdays and family events. Just trying to plan ahead, since my boys are at the beginning stages of a virus. TIA!