Good one. The only suggestion that I have that might go with it for gifts, is instead of giving them concert tickets or something like that I would suggest doing something for them. Cook a meal, clear their sidewalk of snow, or anything other chores that might be difficult for them to do. Gift certificates for groceries, pharmacy or something like that work too.
I am always reluctant to have someone whose immune system is not so good due to chemo go to places where there are crowds of people. Really increases the risk for infection especially this time of year where colds and flus are rampant.
Of course a gift that they can use when they are done is great too. I had one family that all went in and did a trip to Hawaii for their parents when dad's chemo was done. That was great for all of them.
Any advice given is based on my experiences and should not be substituted for any medical recommendations. Please speak with your provider before making any changes.