I've worked in a couple of churches. Funerals are very personal events.
Some people are "please ask everyone to come who knew them. The more the merrier."
Some are close family only, and they don't want it to be generally known because they aren't keen on people who aren't close turning up.
I've seen funerals with 300+ people. I've seen funerals with less than 10 people. Neither is better than the other.
Sometimes the funeral is arranged round second cousin coming back from New Zealand. Sometimes it's assumed that if sister wants to come from Australia she'll be told the dates and make it work for themselves.
Nothing is right or wrong. It's a personal choice.
And I'm looking at the comments on here about how ILs should turn up, or old school friends and wondering how those people know they should or shouldn't come.
I mean I'd be pretty unbothered about them coming in general. Only thing would be I'd feel I had to make an effort to talk to them etc. at a time when realistically I didn't have the head space to do that. I think I'd be touched by the thought, but overall probably prefer to get a text and flowers to show they were thinking of me.
I do have an IL that I would hate to turn up. I'd see them coming as performative and intrusive at a time when I'd be vulnerable.
How does someone know that they'd be seen as being supportive or if they'd be seen as intrusive?
So personally I'd probably prefer it to be people who knew them. Not people who are coming to support me. I'll ask the people I want to support me to come.
In the same way I'd assume if someone thought me being there was supportive, they'd tell me. Then I would make a huge effort to come (and did).
So if you feel someone should come to support you, tell them beforehand, not complaining afterwards.