Does anyone have a source for this segulah?
Emunas,
I think what would be a lot more effective is if the family took upon themselves to be more strict about a certain mitzvah say Shmiras Shabbos…
With all due respect Segulos don’t really work. They can work in rare occasions but only as a last resort. Its ridiculous to think that if 40 or 43 women baked Challah someone sick would magically get better. You realize that if such a thing worked then there would be no Cholim left?
You want to do something big? Get people to do something permanent like learn an additional 30 minutes a day and have your uncle in mind. Or take on to learn the Halachos of a certain mitzvah and start doing it properly or get a few people to go cold turkey on movies, non Jewish music or certain other aveiros like talking during Chazaras Hashatz and Kaddish or other such things.
You have to understand, and its not just you a lot of people don’t get this, if you want something big from Hashem, you need to do something big. Its a chuzpah that people think they will come with some silly segulah and poof they will get engaged, healthy….
Another point is that your uncle, I don’t know who he is or how frum he is but usually if Hashem does something to someone it is to give them a wake up call. Maybe he needs to start Davening better or maybe there’s something he did to someone and he needs to get mechila. Many of the worst things happen to people due to aveiros bein Adam lchaveiro.