Plainly put, there is no guarantee. The only true guarantee in life is that there will be death.
I don't save the still living, usually. I bring the dead back to life. If you want that for your father, there are especially no guarantees. No certainty that hell still be the man you know, none that he'll even be healed from death or the bite. I can take life from one to DO that, but there are few people who would survive it.