Attending a celebration of life

My friend's dad died in Feb and that week I was able to see her - we went out for dinner and talked about him all night. I gave her a card and a small book that made her smile. Her mom is hosting a celebration of life for him in a few weeks, which I'll be attending. I haven't seen her parents in many years, so I'm not close with them as I am with her (we went to high school together but are now in our 40s). Since I already gave my friend a card, do i need to bring something to the celebration of life? I asked if I could bring a dish and she said no. It sounds like it will be casual and fun, focusing on the things he found joy in. I feel bad showing up empty handed.