Hi Mark,
It must have been a big shock for all concerned to have that diagnosis. I personally don't know of anyone who has taken soursop but I have done some research on it and found this link interesting.
http://cancer.vg/en/medicinal-plants/ca ... ulp-leavesAs you know there are thousands of claims out there and no one knows for sure if anything works. What I do know though is that the current medical treatment is very good for testicular cancer and the success rates are high if caught in time. I know of many young men who have even had their sperm saved and went on to father a family for many years after diagnosis - so I would support traditional treatment.
Having said that though I see no reason not o have the soursop in addition to traditional treatment as long as both can be tolerated by the body - and if your friend can afford both of course.
I pass on my best wishes and good luck for his healthy recovery.
Teresa