Premium tax credit

Hi, 

 

In 2020, my spouse was on the same health insurance with his parents (Marketplace insurance). His parents claimed him as a "tax dependent" in the same health coverage. But my spouse and I got married at the end of 2020. Now we want to file join, then how should his parent file their tax? Because they received the 1095-A form that has his name. Please advice 

 

Thank you so much!