Good to see hes finally letting go, no doubt Nassers passing has taught a lot of guys that were holding on to size when they no longer need to,what can happen, hopefully he will make it into his 60s, But I dont think anyone who once weighed 300 pounds plus is going into the 70s and really whilst a shame, 70s to 80s is where your quality of life really starts to slow down,so maybe being big Ron and going at 68 might be better than being normal ron and going at 80, he certainly has had a full life traveling and doing what he loved training and whilst plenty will go on about long life it has to be a life lived as well.
But if I had to make an honest prediction I would say mid to late 50s