It sounds like we all have the same issues to wrestle with.
I will be 70 next month, have blood pressure and arthritis issues, wife in EX health. We live with my wife's sis and husband, both 10 years younger than us and in healthcare.
We just built a new house, upstairs for wife and relatives, basement for me.
I have shifted my focus to operating and video production, but find it hard to part with the "good stuff" on the shelves.
I have early O gauge, some early standard, small amount of classic period standard (the stuff Frank Petruzzo would collect, he was also a good friend), some prewar AF. My favorite stuff now is 1935 to 42 Lionel, Early postwar and 1950's postwar to operate. Also Marx prewar tin, especially Army Trains, and the stuff that we produced as Marx Trains from 1992 to 2004.
Just looking back at that list, it is "too much" for a 70-year old, but I am having too much fun with it now, and my wife knows all of the major auction house owners.
We all have to make decisions based on family and financial conditions, but my vote, is keep the stuff you really like and keep playing (operating) until you no longer know a Hudson from a potatoe. If it provides joy and helps keep the brain functioning, it is good to keep it.