Well, it depends. If the venue is for a very close family member, I think yes, because you're simply fulfilling your duty of piety toward this family member or very close friend, and you are not professing a different religion by attending.
Of course, you do not have to participate in the prayers, it's impossible to participate in non-Catholic prayers. However, a passive presence is acceptable.
Dear visitors of Gloria Dei and all who have already written or who will write a personal message to me. I am grateful for your attention, your kindness, for your spiritual support and especially for your sacrifices and prayers for me. God may reward you!
