Is his name the same or similar to yours then it might overwrite your return. You have to save each return with different names so you can tell them apart. Like if your name is John and your son is also named John or even just the same initial, it will save them with the same name so the second one will overwrite the first return. Go to File-SaveAs and give it a unique name.
Here's an idea. Do you still have 2021 installed? Try opening 2021 program and see if you can get your 2021 return to show up in it. Go to FILE - OPEN. Then save it again with a name and place you can find. Go to File - Save As.
