As a physiotherapists who has worked in many Long Term Care Facilities, I can tell you that sometimes the best thing is to put your parents in a Nursing Home...
If you are working 9-5, your wife is working 9-5, and you have a couple of kids going to school, and friends and this and that, you will NOT have the time to take care of elderly parents with mental and physical disabilities...
The one day that you forget, or you are just overwhelmed with other things in your life, to check on your parent, will be the day that they fall in the basement and break hip and stay lying on the floor for 5 hours before somebody discovers them...
When I am treating the elderly with broken bones, that's the most consistent story I get from them...They were home alone, tripped and fell, broke some bones, and they either had to crawl to get to the phone or they were lying on the floor for 4-5 hours, sometimes more, before they were discovered...
From my experience I can tell you this, if you want to take care of your elderly parents with mental and physical disabilities, then you or somebody in your family will have to give up his/her life...