There is a weird quirk in the tax law with the stimulus payments ... you get an ADVANCE based off what was on your 2020 return however the credit is really for the 2021 return ... so if she has 3 people listed on the 2021 return her credit is 1400 x 3 =4200 less the 2800 she got in advance = 1400 on line 30 of the form 1040 and it is legal.
If you got the stimulus for the same child in advance and you are not claiming that child on the 2021 return you don't need to give it back ... so this is a legal "double dip".
