Sorry, I too think you are totally out of line here. If your parents have made their wishes clear regarding the use of blood, you have no business interfering or trying to override their wishes. Would you want them trying to talk you out of a blood transfusion?
Of course, many older JWs have no idea about all the treatments that the Society has now said are permissable. Most of them think of it as very simple, black and white issue: no blood. In some circumstances it might almost be better to get the HLC involved, I know when my brother-in-law was resisting taking albumin, the elders were practically begging him to take it, and he finally did give in, fortunately.
But the idea of trying to force a medical procedure on someone, especially an adult, is abhorrent.
No Apologies