He's a perfect storm of all the excesses/abuse in professional bodybuilding. Nerve damage, drug/hormone "kick back", structural deterioration and destruction, etc.
Coleman's current physical condition is less age and much, much more that stated above.
As Ray so succinctly stated, what made Ronnie, broke Ronnie.
He achieved muscle glory and walked the planet a true freak but will now live out the remainder of his life a wreck.
Was it worth it? Only he can know.