Thank you so much for your support during these challenging times. It is complex indeed and does not become easier. I have the following concerns at the moment. It seems that mother is more comfortable selling her chometz through her Hillel School where she teaches. On the other hand she is concerned and is a bit frightened actually to sell through a mainstream charedi rabbi to whom she would have to reveal her home address and to whom she would feel pressured to make a donation. Considering the whole idea of leaving actual chometz in a refrigerator/freezer is bediavad to begin with as the Rav himself has stated in combination with fact that my mother teaches at Hillel, which is officially a modern mizrachi school. My question is: Perhaps I should tell her that she can sell through Hillel, but I might not be able to eat the chometz after Pesach. I also would like to know about the refrigerator door- about half of which she is “selling”- does this render the refrigerator door muktsa on Yom Tov?

ב"ה Shalom, I am sure the sale of Chametz through the local school is done properly and is completely reliable . I am sure there are Rabbis there who know how to carry out the sale of Chametz and it won't be their first time. Considering their sale unreliable, G-d forbid, would be Insinuating that an entire community has not sold their Chametz ,which is a very severe accusation, which we must be extremely careful of. Each community follows the guidelines of their Rabbis who are G-d fearing people. From your question, it is obvious that you feel an uneasiness with Chametz being in the fridge. But if the Chametz is properly set aside and marked, it is not forbidden since the Chametz is sold. I' m sure in your home you wouldn't do that, it's completely understood, but there is no prohibition being violated. I have seen this done as a child while living in Borough Park, by completely frum families. I've also explained in my previous answer that although we refrain from eating anything which is not labeled Kosher for Passover it doesn't automatically make the product Chametz . It is all dependent upon the ingredients. I edited this answer after I had already sent it to add, that I have heard now from many Rabbis in view of the complex situation so many people are in due to the Covid 19 virus, to allow the sale of chametz EVEN FOR PRODUCTS WHICH ARE "CHAMETZ GAMUR" , they are 100 % Chametz. Therefore, in my humble opinion, you should not tell your mother you will not be able to eat the food from the fridge door after Pessach. There is no reason to do so. I think you should give your mother, who is not fully observant , a lot of credit for the efforts she is doing for Pessach to sell the Chametz and make a Seder. As a rule, we should not allow a "chumra" a stricter adherence of Halacha to come in conflict with Shlom Bayit. Only if something is totally forbidden we have a problem we need to confront. The items on the refrigerator door do not make the door "Muktzeh" they are insignificant in regards to the rest of the door. Al l the best