The Kallah and the Mother in Law

Once there was a young man who spent much time and energy every day taking care of his elderly mother. He did not hide this fact from the shadchanim with which he came into contract. On the contrary, he told them up front that he planned to continue taking care of his mother after marriage as well and wished to find a wife willing to assume this burden.
Understandably, this cut into his prospects. Although he was a very eligible young man in other respects with sterling middos, virtually no girl was willing to saddle herself with a young man with such harsh obligations from the outset of marriage. Why should she take on such an unbearable burden?
The shadchanim were afraid that this young man would remain single his entire life. Clearly, the mother should be placed in one of any number of frum old age homes where she would not be a burden to a new couple just starting out on life.
One shadchan broached this issue with the young man and advised him to ask this question of Rav Shlomo Zalman Auerbach, zt”l. The shadchan. who had hoped that the great posek would tell this young man to drop his foolish insistence and be realistic about shiduchim, found Rav Shlomo Zalman’s response to the bochur very surprising. “You are absolutely correct to search for a ba’alas chesed in precisely this manner. If a young lady is unwilling to take care of your mother, she is clearly not for you.”
After a time the young man finally found a ba’alas midos willing to take on this incredible self-sacrifice. She was willing to live in a small apartment with her husband and her new mother-in-law and help care for the elderly woman.
When the young man came to tell Rav Shlomo Zalman the news, he was completely floored by what he heard, “Mazel Tov! Now you know you are getting a true ba’alas chesed. But you must immediately start searching for a good home for your unfortunate mother. Actually placing such a burden on your young bride-to-be is unfair and is simply not an option!”