Marvin,
Lets just deal with one case. This is possible and it is probable.
You have a JW with bowel cancer, diagnosed at 84yrs, had cancer for say about 4yrs. The doctors cannot be sure how long. The patient has the tumuor removed, as JW still had a blood transfusion, non-JW family force the issue, the patient lives for a further 12 months. The patient got Df'd.
Why did the JW die?
Marvin, give it a rest now, there are too many variables, you cannot do the stats on blood issues, in my veiw none of it is credible I am afraid.