polisha chosid – Respectfully, a Rebbe is not a posek and a posek is not a Rebbe. I mean no disrespect, but that is the fact.
Besides, you yourself write that he was under doctors orders, as such a choleh, which allows for kulahs and to be somech on the mattirim.
As far as not eating sandwiches, what is the basis for that chumrah? I am always interested in learning of new chumrahs to take on and would take this on if explained! Did he not eat korech at the seder?