It should lessen the stress on the heart I'm sure. Though from what I've read the changes to the heart are permanent to a large extent.
But if Ruhl were to get completely off he would be in an extremely weakened state and whatever health issues he has might finish him right off... just complete speculation on my part, just a hunch. Tapering off would be good, but imagine if he's been on daily thyroid, steroids, gh, insulin for a couple of decades straight and stopped all that at once. Sounds dangerous to me, the whole system would go into shock, blood sugar would be all over the place, thyroid all messed up, huge water loss all at once etc. 
I remember on musclemayhem a decade ago or so when cswole said he got off his bottle a day habit. He was complaining of feeling like utter shit, couldn't sleep for weeks etc. Sounded like a junkie going cold turkey. 
The changes to the heart are permanent, however massively reducing the workload it has to do by losing weight is going to have a significant benefit. Additionally there are still plenty of things that can be done to maintain and improve heart function, even if it is compromised.
A genuinely healthy diet that is low in calories (not 400 grams of lean protein a day as muscle and fitness would have you believe) would help.
I believe any bodybuilder can sufficiently turn his situation around. Ok, there are some things that cannot change, and there may be some lifelong increased risks that they will have to accept, but many things can be done to reduce those risks.
Unfortunately most bodybuilders both competitive and recreational, are either limited by their intellect, lack of common sense or simply "head in the sand" merchants who cannot make the changes to prevent their early expiration.