A.V.
It's only been a few weeks and he's had a big change. I'd continue to work with him and the teacher. I would show enthusiasm for school and maybe she can pair him up with another nice kid so he has someone to get to know one-on-one. Make drop offs short and happy. It sounds to me more like homesickness than really hating this school. He just can't articulate that he misses his friends. Can he write his old teacher a letter or something and maybe she can write back and say something like she is glad he gets to live somewhere interesting like x place and hopes he enjoys his new school?