Being a single person who does not cook often, this would be a fantastic idea to see come to fruition.
On the other hand, as a person who skews toward the overly-cautious, I would be concerned about the lack of sanitation inspections, servsafe certifications and other safeguards that commercial kitchens adhere to. Also, how could you be assured that Mom is not in a dire financial situation, re-heating her special curry to sell at a marked-up price - a special curry that went bad several days ago.
Law-, permit- and zoning-wise, I am not sure of what would need to be done. It is an interesting idea for sure, albeit one that would take some serious planning.