I have the same issue, my hubby spends a fortune on takeaway food. I try to make him a larger version of whatever I am making the boys for their school lunches. Some options are:

Pasta salad
A crunchy salad with a tin of tuna.
Regular sandwiches and a chunk of home made fruit cake (bake a large one and cut into 4, then freeze 3/4. one quarter should do 3 lunches )
Curried chicken risotto, delicious cold.
As he has power, can he get some pot noodles and cook with boiled water?
Mexican chicken, salad, sour cream and guacamole in a wrap.

HTH