I am still baffled as to why anyone would think a 6 year old boy would want to attend a wedding ceremony. Well, maybe one out of curiosity, but after that, it would seem to be torture. So, why would the aunt make the poor kid go when there was all of this neat stuff going on with other kids? We don't know how old the second boy is.
I personally don't like the ceremony except for my own children's, and I made ours as short as possible. (Eighteen guests, five minute sermon about being kind and nurturing each other and keeping God on our lives, the magic words, and we were out of there.)
The kid would probably prefer dinner with his new friends, and the dancing afterwards is kid-friendly, so that's fun, but they were invited.
That makes me think the aunt was doubly rude.
There are plenty of 6 year old boys who would. There are plenty who wouldn't. Age doesn't rule it out. Gender doesn't rule it out. Making sweeping assumptions is generally going to lead to erroneous conclusions.
Most of the kids I grew up with were used to regular mass or church service every Sunday plus special services on holidays. They would not have been bothered by a wedding and most would have enjoyed a special service like that. Not all but but most. A lot of them also would have enjoyed sitting with the adults and eating dinner with them. Not all but a lot. It is entirely possible the 6 year old in this situation would have enjoyed the ceremony and the dinner.
Now, if he wasn't invited and it was made clear his mother should have accepted graciously and attended herself. If there was confusion, she should have been subtle about her absence. Either way, the big production was out of line. I just find it incredibly presumptuous to make those kinds of generalizations about how a kid "must" think/feel.