Q. Is there any way he can still receive either stimulus payment?
A. Yes, he just has to wait until 2021.
In essence, the stimulus check, received in 2019, acts as an advance of his 2020 income tax refund. This means when he prepares your 2020 income tax return, in early 2021, there will be a line to include the section 6428 credit (line 30 on the 2020 form 1040). The credit on his 2020 return is subtracted by any amount received as a stimulus check in 2020. If the amount he received (0 in his case) as a stimulus check is less than the credit he is due, the difference will be included as part of his 2020 refund.
As others have said, this is contingent on him not being eligible as your dependent in 2020.
