I got told one of my students is a lost cause

Hello! Ive recently been given a new permanent position as I was a floater for a few 1 on 1 positions while the district fixed last years fuck up but thats neither here nor there.

Im a Teachers Assistant, one of the students in the group ive been given has been a fairly difficult case these past few weeks. He dosnt understand things in classroom environments from what ive learned and ive been having to pull him into a sepreate classroom to go over the work with him there. Once hes done complaining about not wanting to do the assignment he usually understands it fairly quickly until he is back in a classroom environment then all my work dissappears until hes 1 on 1 with me again. The head teacher has told me as well as another TA that its not worth the effort.

I dont want to give up on him though because once i figure out how to explain the work in a way that makes sence to him he absolutely lights up and gets so excited about knowing the work. Personally I think its a confidence thing with him and im trying to figure out new tricks to get him to focus a bit more in classes like history or english. Ive noticed he loves to fidget with his ipad or whatever is infront of him so maybe i should get fidget toys for the classroom? Im just unsure what specifically would be most effective as this is a new age group for me. Up until now ive worked with Elementary students and now im with middle schoolers. I want to be the best for these students. I want them all to have confidence in school. I know they can all understand it if they believed in themselves for even a second. Im just running out of ideas for this specific student.

Idk if this is where this belongs but i figured anyone here would understand or be able to help more than other sub reddits ive seen. Thank you for reading though