family member diagnosed with cancer - please help with food and other advice

Dear IL,
One of our dear ones has been affected with cancer of the colon - currently the patient and other immediate caregivers ( basically, rest of the family) stay in chennai India. We (staying abroad)want to give them as much infromation regarding diet etc but we are ourselves overwhelmed by info online.. Everybody suggests raw fruit and vegetable.. but for elderly members who are accustomed to tea/coffee, rice/sambar etc etc.. so difficult for them to make transition.. another thing, big headache in finding correct shops for substitues like brown rice.. with all this going on, I really would appreciate if any ILs know of any friends/acquaitances who have handled cancer treatment with a focus on nutritious food complemented by surgery/chemo/medical stuff..
When we hear the complaint of constant bitterness in mouth (due to antibiotics) etc, we feel so helpless.. we only mechanically suggest 'eat this fruit, drink this juice' etc.. any real recipes would be greatly appreciated..

Looking for suggestions,
Savitha