What to expect at a Celebration of life event?

I’m sorry for the loss of your friend. We went to a similar event a few years ago organised by our friend’s wife. As my husband was a close work colleague he was asked to give a talk about working with him and their friendship outside work, mainly around cricket. Other people had also been asked to talk about other parts of his life. A cousin in Canada sent a lovely recording. His wife read a lovely poem that she had written. There was food and drink and it was a lovely atmosphere. I would imagine that if the invitation says between 2 and 5 people will be expected to arrive at 2 and perhaps stay the whole time. Obviously, if you don’t want to stay the whole time, you can make your apologies. I expect that her son will ask you beforehand if he wants you to speak but perhaps prepare a little something just in case. I hope this helps.

A sad time for you.
I’ve been to one such event and it was exactly as SadGrandma describes - sibling, child, grandchild, work friend, neighbour all talking about the deceased person from different angles. Bits of music. Pre-planned and printed programme. It was in the morning with a buffet lunch afterwards. If I were you I’d def arrange to be there at 2 and assume the dress code is smartish casual unless told otherwise.
You will probably find it a friendly gentle occasion. I hope you enjoy remembering your friend.

Thank you for such kind and helpful replies.