Hi My Dad Has Had Prostate Cancer For Past 4

Hi my dad has had prostate cancer for past 4 yrs which has now gone Into his bones he has had 8 treatments of chemo and after getting sepsis a year ago decided no to continue with last two treatment things since have been ok but tonight he has shown me tht his nipples have what looks to be like dark brown scabs although they are not scabs it is just his skin it is quite bumpy it's doesn't hurt, itch it is not sore any ideas what this can be?