1. Get the paper to stop being the system
Most missed payments start as a letter that sat unopened in another city. Have their mail forwarded to you (USPS lets you set this up online), or redirect the important senders one by one: the electric bill, the insurer, the county tax office, the pharmacy. If your parent can scan or photograph letters to a single email address, that address becomes your inbox for everything that matters. Paper you never see is paper you cannot act on.