Sir, My Mother(70 Yrs Old) Was Treated For Aplastic Aneamia.She

Sir, my mother(70 yrs old) was treated for aplastic aneamia.She was treated with Hourse ATG during 10th july to 14th july. After ATG she has given wysolone 50mg per day + Reolade for 21 days. She is now on immuno suppressive treatment. After 2 and 1/2 month she is suffering from weakness. What is the cause of weakness and when she will come out of it?