My Sister Has BPPV. Her First Episode Was November 29th,

My sister has BPPV. Her first episode was November 29th, she had the flu that caused the vertigo. She started to feel better but then at the 2 week mark she seemed to have started from the beginning. She can hardly walk even with assistance and now is saying she has double vision and a bad headache. She was seeing a physical therapist who was trying to get the crystals out of the canals. She was feeling better Monday January 16th and suddenly the double vision and headache started Tuesday night. She has gone to hospitals and neurologist. What can we do to help her?