My wife is a kosher giyores while her mother is not. My mother in law lives in our 2 family house and watches over our type 1 diabetic 8 year old son when my wife and I are at work. Can we trust our mother in law to cook for our son properly even when we turn on the gas range before we leave for work? Is this a pikuach nefesh issue for our son where even bishul akum would be permitted? My very frum sister insist we can’t trust the mother in law since she doesn’t have a chezkas kashrus when we are not home. I should also mention that my non Jewish mother in law worked and cooked for an elderly, chariedish couple for 20 years and so, is very familiar with Kashrus. Thanks.
Your sister in law is correct in aspect that she doesn’t have a chezkas kashrus, however nevertheless it is permitted for you to turn on the fire and your son may eat from it. The reason is not because it is pekuach nefesh, but because it is a need of the child and since bishul akum is an issur d’rabonon, it way be given to him, since he needs his food.
Rashba brought in Biur Halacha 343 D:H M’divrei Sofrim.