Prostate radiotherapy and side effects, what foods help?

Hello, my 70-year old stepad will be receiving 5 days / week radiation for his prostate (it was already removed, but markerrs returned), and i'm wondering how can i help him and what things to buy?

Should he be drinking aloe juice daily or should i buy some gell to apply daily on the area? what about other vitamins, foods, minerals, etc? anything else i can buy to make his life easier?