Hey, I'm going to a funeral tomorrow for my grandpa...

We don't mind if the in laws choose not to go. We would rather have people there who truly care, not people who feel obligated to go. I'm sure a lot of people attending the funeral feel that way. Your father in law is probably the minortity.

If you don't care (or don't care very much), then don't go.

I know that some of my family members aren't going to my grandpa's funeral tomorrow. One of my cousins has bad PTSD and another cousin is too devastated to go. Others have similar reasons. So, even people who care choose not to go.

I chose not to see my grandfather's body today during the wake. It's not because I don't love him. It's because I didn't want to see him that way.

We don't judge anyone for not attending. We know that everyone has their reasons. Hopefully your family and your in laws feel that way too. Your father in law is just one person