I'm sorry to hear that, Marg. A dear friend of ours had non-Hodgkin's lymphoma and went through 8 rounds of chemotherapy, so I know how hard it can be. It is not unknown for the patient to react more strongly against the chemicals than against the cancer itself, which makes treatment very difficult. She's fine now after a year, but the only way she said she could keep going back then was to have a number of milestones to look forward to - daughter's first day at college, half- term, Christmas, and so on. She found that it helped her enormously. Perhaps the daylilies in July are a target your brother could aim for.
With much regards, Shanti.