I spoke at my best mates Dads service, he was more like a member of the family as my mate has been "on the scene"
for more than 20 years. I found it best to keep it fairly simple , and also add a dash of humour and of course a couple of well placed self deprecating insults. People generally don't want gushing or " maudling"
Hope it helps, and sorry to hear your news.
Good luck.