I'm assuming your friend didn't go to a qualified therapist?
Her work at the time paid for a therapist to come in (it was a big company and I'm sure they wouldn't have organised anyone dodgy). And her lawyers proved in Court that the therapist was legally negligent because she won the court case (millions). I've been through that court process, up to the point of seeing barristers, even if someone is openly negligent (as the drs at the hospital I went to were), it's not enough to prove the legal definition for negligence. You have to also satisfy the 'but for' test, i.e. the stroke wouldn't have happened 'but for' someone else's negligence. For me, we could prove one part of negligence. We didn't satisfy the 'but for' test because the stroke was already happening in hospital (they just gave me adrenalin which made it worse), but there wasn't enough evidence to support my claim (we bowed out before taking it to court). But not my friend. The court had enough evidence to say her stroke wouldn't have occurred 'but for' the massage. So someone did something they weren't meant to