Unfortunately, the Organization doesn't seem to care about the burdens they put on the elderly in general, let alone an 82 year old elder. My brother in law nearly had a nervous breakdown several years ago from the stress of being an elder. He was only about 45 at the time, but because of two moronic, power-tripping elders, they lost every good elder they had, because no one would do anything about it. I told my b-i-l a year before he stepped down that he needed to quit while he was ahead, but because he was the only decent elder left in that congregation he felt he was abandonning the congregation so he stayed. The last straw was the day he and my sister were out for breakfast and as he reached for the sugar, she saw his hands were literally shaking. So she told him to step down.
The sad thing is, if your dad has been an elder for 50 years, that's a big part of himself that he might feel he is giving up if he were to step down. One thing you might suggest is that he tell the other elders or CO or whoever it is they report to, that he just needs to take some time off----say 6 months. You could stress that he's not really stepping down as an elder, but he's just taking a break----sort of like taking a 6 month unpaid Leave of Absence from work. You could then tell him at the end of 6 months, if he wants to resume being an elder, he'll be in much better shape to. I can almost guarantee you though, that at the end of 6 months, your dad will probably realize he doesn't want to be burdened with all that crap again.