I'm at my grandfather's funeral today, and literally half the people there were wearing something I thought was completely inappropriate. One dude was wearing a fucking batman T-shirt and fucking jeans. My cousin was in a full blown cowboy get up complete with jeans, flannel, cowboy hat and boots with a giant ass belt buckle. Keep in mind this kid was born and raised in northern Michigan. He hasn't rode a horse a day in his life.
Now I'm not expecting everyone to show up in a suit and tie but to me, jeans are absolutely unacceptable funeral attire.
Was the same at my granddaughters wedding. Sure, it was a smaller, southernish town but they're big enough to have a Wally world. I bet they sell sport jackets and ties at least. Even the grooms father didn't have a suit one, but I did and I was the bride's grandfather. Of course, after the reception dinner, the bridesmaids and groomsmen changed into jeans and a wedding-logo'd tee-shirt and I even took off my coat. They were kids and there was dancing so I can see that.
No one seems to think the couple will be looking at their wedding pictures for the rest of their lives. Maybe I'm just old-fashioned and it won't bother them, but I look at it as a matter of respect.
Condolences to you and yours. Try to focus on his life, not those people.