I’d say if you are no longer getting nocturnal/spontaneous/morning erections, and your penis is in a constantly flaccid state, then yes – you should try to stimulate it as much as possible, to help provide fresh oxygenated blood flow to prevent possible tissue fibrosis/collagen deposits.
See the studies at the top of the “Sexual Side Effects” section for more info on this, and some strategies for penile rehabilitation therapy.
Also, get your blood tested as outlined on this site (Hormones & Bloodtests section), because if your problems are due to low levels of Testosterone or other imbalances, you will need to try and correct those… obviously the sooner, the better.