If you really want to try it, it's not impossible, just supplement calcium, but you must grind the cow's teeth into fine powder, otherwise it will be packed in capsules. Once it enters the stomach, the capsules will dissolve and the particles will run out, and the sharp corners will scratch the gastric mucosa. The gastrointestinal tract of the elderly is very fragile.
It is more reliable for cancer patients to give him some health foods such as protein powder, bovine colostrum powder, spirulina and propolis.