Relatives who hint "I need money." How do I respond?

My mom (in her 90's) receives letters from grand-daughter, which describes: trying to save money, everything is so expensive, I do my own family haircuts to save money, kids need new shoes but they are so expensive, we are driving an older car and it needs repairs, school supplies are so expensive, daughter wants to do dance lessons but no money, etc etc etc.
On the one hand, my mom is thrilled to receive a letter from her grand-daughter, but then my mom says to me, "what do you think, should I send her some money?" mom is not dirt-poor, but she really cannot be sending out $50 every month to this one grand-daughter. I've told mom, I think you need to save your money for yourself, and the grand-daughter's husband is very well-employed so why would they need any money?
It seems really coarse that this grand-daughter ALWAYS mentions money in her letters.
However, on her fb, she announced she had finally paid off her mortgage.... which is quite an accomplishment for someone only 40 years old---it does not sound to me like she has any money "troubles".
So my question is, as my mom's poa, should I write a letter to this grand-daughter, and ask her to stop mentioning her money "troubles"?