Sounds like your son's system is taking a bit of a kicking..

Consider two things ..

First Candida. It is a little yeast that is always with us, but when we get run down, or use antibiotics, then it quickly gets aggressive. It causes bloating, depressions and damages the immune system. Consider starting a Threelac programme to keep it in check and remove its burden from the equation.

Second Ascorbate. Whenever our systems are under attack, loads of free radicals are released which quickly mop up ascorbate. You have not stated your sons intake level, but it is highly likely that his body demand could be in the 50g per day range or even higher to satisfy the demands of free radical neutralisation and still leave free ascorbate in circulation. A word of caution however. Some cancer therapies rely on free radical production to kill the cancer cells (i.e. radiation therapy). Using ascorbate will simply negate the potential positive effects of the therapy, so ALWAYS discuss its use with your consultants.