We have medical marijuana here in Az. A couple was using the oil extract for the same thing for their son until the Ag deemed it against the law saying only whole pieces of the plant can be used. They recently overturned that and needless to say it's a victory for all parents in your situation, at least here. I don't use it (never liked the effect), but I can tell you that that when you use it as a medicine, it is very effective. It would really help your father in law if he is having stomach problems due to chemo. Good luck.