appstore is randomly asking for password to account for free apps.

so, my firestick's remote broke and i'm trying to download an app to use as a remote, but when i try to, it asks for my password. issue is, i'm on my dad's apple account for the appstore (not my phone, just the appstore. long story, not getting into that.) and i don't know his password. how do i turn this off?? it's NEVER done this before. i literally got a free app yesterday abd it only needed face id. what do i do?? is there any solution for this??