Should you respect someone who insults a dead loved one?

At a christmas party two years ago, I was at my uncles house and my dad was talking.

My dad said something (which wasn't offensive) and my uncle goes (do you see your dead wife's ghost at night)? and he and his son kept laughing.

My mom passed away in 2002 and I feel they have no respect.

Honestly, what do you think about what my uncle said? I feel it's very disrespectful.

If my most respected uncle was there, he would have ripped them apart.