Stimulus IEP#3received for 2020 tax return and partial 2019

My husband and I divorced in 2020.  I filed my 2020 tax return Feb 21, 2021, and have a received a stimulus based on that tax return  (head of household with one dependent)  

I also received a $4847.36 stimulus based on my 2019 joint tax return with my ex-husband.    I believe this deposit was made because my ex-spouse had not filed his 2020 tax return at the time the stimulus was issued, and a stimulus based on our 2019 joint tax return was issued.  The joint stimulus was reduced based on our joint income in 2019.      

Ex-husband has not received a stimulus and he wants me to advance $2800 stimulus to him (which is what he is entitled to using his 2020 tax return as head of household with one dependent).  

Any concerns with my giving him that $ directly or should I return the joint stimulus to the IRS and have them sort it out?  If I did that, what would happen to the remaining portion of the joint stimulus?