I have tears welling in my eyes--what great kids!
When my stepmom died (also about 57 after being married to my dad for 25 years) we called her service a "Celebration of Life". And that's what it is. You celebrate their life by talking about them, laughing at funny things they did, etc. It's sad, but it's how you keep them alive.
I'm sure while the waiter had no idea it wasn't the fun type of "party", he will not make that mistake again.
Sending out huge hugs to you.