What to wear to a "Celebration of Life" Party?

Andrea • Tommy arrived 12-5-16 ❤️
Hi guys! I recently lost a mentor/ colleague who i really loved and cared about. Today his family is hosting a "Celebration of Life" party. From what I understand there will be no formal service, just a gathering. I imagine it will be similar to a reception that follows a memorial or funeral service. Anyways, what do I wear? Do I still wear all black semi formal/business attire? Or is it more casual? Are jeans appropriate? Should I wear some color since it's a "party"? When I spoke to his wife I got the impression that she wanted this to be "fun and not sad".... I'm so confused. 
Thanks guys for any help!