These guys have already been treated for testicular cancer. If either is needed the second time around, then something different must be used. If you had radiation before, then you might need surveillance or chemo now. If you had chemo, then you might need radiation or a different chemo protocol. However, be aware that just because you had testicular cancer twice does not make your case more severe.
Surveillance is still an option and the cancer is still very treatable.
The guys in the third group have a different concern. They haven't had any treatment before, so all treatments are available. However, simultaneous bilateral testicular cancer is really rare. It definitely can happen, but it is rare enough that they probably should ask for a second opinion on the ultrasound before letting the doctor do any cutting. Few doctors will have seen any of these types of guys before.