About Red eared slider

My mom decided to purchase a tiny turtle at her local shopping plaza for my children. When she brought him (or her) home I did research and we dis our best to give him a good life... but he's getting too large and too expensive (I am a single mom of three and disabled). I'm worried he isn't getting what he needs (mainly space) and he seems sad. I don't want to give him up but if someone else has the means to give him a good life then that's where he needs to be. If you know of anyone (sanctuaries/ good people) that can take him please let me know! He's approximatly 5 years old and approx 7/9' long 5/6' width

Bristol County
Mansfield, Massachusetts