My daughter is turning 18 in February and will lose her ss benefit. What happens to that money? Can it go to another child even if that child is already drawing a check?

Hi,

That money simply remains in the Social Security trust fund if it can't be redistributed to another beneficiary on the record.

The only way that your daughter's benefits would be redistributed to another beneficiary is if the other beneficiary's benefits are being paid at a lower than normal rate due to the family maximum benefit. For example:
Jane, Julie and Joanie are receiving child's benefits on their father's record. The family maximum benefit payable on the father's record is $1800, of which the father receives $1200. That leaves $600 to be divided between the 3 daughters, or $200 each. If one of the daughters in this example is no longer eligible for benefits, then her benefit amount would be redistributed to increase the other 2 daughter's benefits to $300 each.

Best, Jerry