It's alright for them to say you can sort it after they've gone!
Yes, this is outrageous. You may say this about a house or other assets, where it takes over your life for a few months to deal with it all and dispose of as necessary, but you can then draw a line under it after that. He is a human - and not even a particularly old one - and they're effectively committing your life until your old age to looking after him.
In fact, he's the same generation as you, so he could even outlive you. What would happen then? Would your children (if you have any) then be expected to take over responsibility for him?!
They might think they're being kind, but they really are not helping anybody at all. In an 'ideal' world, you will have children who are fit, healthy and able-bodied, with no vulnerabilities or challenges; who will become independent adults many, many years before your time comes when you have to say Goodbye. However, if you have a child who will never be able to live independently, it is your basic duty to make good, solid, sustainable provision long in advance of your own old age and death.