Is it just me? I had radiotherapy for oral cancer in Jan/Feb. My mouth was (and still is) very changeable, swallow was affected, tastebuds a mess (still are). The hospital would only prescribe a certain number and some were vile (to me) but once I settled on a few flavours I bought my own online. It was cheaper and easier than making my own meals that I then found I couldn't eat. However, if we're in a hurry both hubby and I swig a couple down before going out to at least have some sustenance and avoid feeling light-headed. You can also use them to make milky puddings, custard etc.
In any case, radiotherapy affects metabolism and can mean the good cells do not repair as easily, so you are advised to consume about 500 calories extra every day for about a year after your treatment ends. So don't chuck them away just yet. If your DH has only just finished RT don't think the worst is necessarily over cos new symptoms can appear months after treatment has ended.