[RiseofAsia]

Apart from FD and some insurance retirement plans, my mom relies on an allowance from my siblings and me. So the irony is that my aunt is NOT receiving an allowance from her own children, but getting a cut from my mom's allowance from my siblings and me. She evens complains that $800 per month from my mom who is long retired, is not enough.

Very easy to solve the issue lah.
Next time if she makes a fuss on your mother again.
Ask your mother to get angry and scold her back.
Then dont answer her phone call if she calls and dont give her any allowance from then onwards. Money shd be given to grateful person not ungrateful person.

Once she has learned her mistake, then your mother still can give her some allowance but must cut down, just cook up some excuse.