I think the biggest thing I want to remark here is that he needs to go to the doctor frequently while he's running these experiments. Once every couple of weeks or once every month. He could be doing serious harm to himself and he won't know until it's too late. Blood work might also give some interesting insights, such as "his bad cholesterol levels are lower than I've ever seen, this is amazing!" which would be useful in helping to push his encouragement of it.