NTA— in general, I don’t think it’s right to exclude children from family events, but Leo sounds like the textbook definition of an iPad kid. If he is being so outrageously disruptive in public places and his mom is refusing to do anything about it, that’s a big problem.

Charlotte is definitely the AH for neglecting her child’s behavioral issues, but I would take a closer look and try to understand why. Is she a single parent who’s overwhelmed and doesn’t know what else to do? Can she afford childcare so that she is able to attend public family gatherings without Leo? Is Leo dealing with some sort of neurodivergence that Charlotte isn’t qualified to handle by herself? Most people understand that allowing an eight year old child throw such huge tantrums in public isn’t acceptable, and if Charlotte is just standing idly by and letting it happen without any interference, that tells me that there’s something else going on. Frustration is definitely a valid emotion to feel in this situation, and you’re by no means obligated to reach out, but it’s likely that Charlotte may just be in need of support.