It sounds as your daughter receiving Supplemental Security Income (SSI)
That is a Federal income supplement program funded by general tax revenues (not Social Security taxes):
--It is designed to help aged, blind, and disabled people, who have little or no income; and
--It provides cash to meet basic needs for food, clothing, and shelter.
The amount of SSI is based on your daughter needs so if she has $250 a month income - that income is considered (regardless if it is taxable or not).
$733 per month is the maximum SSI payment.
So - if you stop sending her the money - and she would inform the SSA about changes in her income - she most likely will receive larger amount.
Here are requirements to report any additional income for SSI recipients - see attached.