Not sure about the accelerated hair loss while on deca bro, but there is an article I studied on here about a year ago which linked finasteride to long term erectile dysfunction. If you do a search on the compound I am sure you will find it, sorry I cant be more help on that.
Having personally used finasteride and having had ED issues shortly thereafter, I will never ever use it again. Hair loss as you know increases while on a cycle for most people, but ceases the moment you come off. Only people who are prone to male pattern baldness will find that the hair doesnt grow back as fast or at all.