Brain surgery for arteriovenous malformation in the brain stem.

Three years ago,November,2022, my 55 yrs old brother was diagnosed with arteriovenous malformation in his brain stem and had brain surgery for it. After the successful surgery, the surgeon prescribed physical therapy and said he would be walking with the help of a walker within six months and back to normal life within a year of the surgery.However despite PT,OT and Speech therapy,my brother is now
wheel-chair bound.The whole right side of his body is paralysed, he can barely speak,see out of right eye,and has constant pain in right hand,leg and foot. He has been to several different nuerologists and neuro-muscular doctors,undergone multiple tests,etc. only to be told there's nothing to be done for him. He would like to know if anyone has had brain stem surgery and experienced a similar outcome?