1. My friends did this and decided to pull their kids out after a couple of years because even though the children were getting lots of attention at school, it couldn't make up for the fact that there was socio-economic disparity and that most of the children just were not supported academically and in other areas - so there wasn't a peer group at all.
THIS.
But, OP, it truly depends on whether or not there are any others there like your kid.
I taught in a Title I school many years ago. There was one child in my first grade class whose parents sent her because they truly had a giving and generous social philosophy. She was the only child whose parents had a college degree--and, I suspect that most of my kids came from families lacking a high school degree. Her parents were professionals: a journalist and a nurse. The child was lovely and got along with her peers--but academically and socially, she did not fit in. She got along, but the gap was too great.
At the end of the year, her mom came and told me they were moving to another school boundary. She shared her concerns. They did not move to an elite neighborhood, but to one that would provide a greater span of socio-economic kids. I told her that I thought she was doing the right thing. We had never had this discussion until then.
That does not mean this will be a poor fit for your child. I hope there are other kids there who are not so academically far behind him.