You can put your best foot forward and do everything right and it will not mater if the other person is not healthy enough to do the same

Do your best, but it is not a failing on your part if you do your best and someone still gets mad at you, or is unable to understand you, etc.

This is an overly simplistic way of putting it but I think it helps get the main thrust across. I wish I could remember an old buddhist quote that feels really related that I think would also be helpful but I cant :/ searching just turns up a bunch of bland Pinterest quote garbage lol

Hope this helps :)