I went with my husband to all of the appointments. The imaging is very precise so it takes a little while. They will set him up in a certain position on the table and stabilize him so he stays still - he's not strapped down or anything they just want to ensure he's in a stable position for imaging so they can set him up in the exact same position for surgery. There is, however, no room for modesty here, FYI. My husband told me after that every possible good looking nurse came in and adjusted him here and there and everywhere and that flimsy little gown was not much use ...
I believe you will be requested to use an enema before the procedure - you need to be cleaned out prior to most of Brachytherapy procedures - that's sometimes the worst part. At our hospital they set you up in a room with a bathroom so you don't have to run anywhere (no pun intended)!
I was not allowed in the particular procedure room for the imaging but I was allowed to stay right outside. If you're husband is anything like mine, he's been through several physical exams and, fortunately, or unfortunately, it's becoming second nature so the actual imaging is not that bad. I do recall, however, that he was tired after but hospitals in general make his tired.
Let me know if you need to know anything else or just need a shoulder - I'm happy to help you where I can.