nor is my flight instructor rating valid, because once one is physically impaired,ones intellectual ability is also impaired
You're in an unfortunate position for sure, and I'm sorry that you can't do what you enjoy doing any more.
Just thinking back to the purpose of the RPL though, wouldn't giving flight instruction be somewhat at cross purposes with the "R" of "RPL"? Allowing formal, log-book certified flight instruction might open a bit of a Pandora's Box.