My grandfather in particular was an agricultural scientist, he loves plants and outdoors and working with tools, and used to be very energetic.
Now he has to sit on a wheelchair, and grows bored of watching TV and reading (it doesn't help that his eyesight is very bad).
Their current enjoyment are their grandchildren, and we've grown old. I just hope they can get to see their grand-grandchildren (my girlfriend and I expect to have children in 2 to 3 years' time), that might get them some enjoyment again.