1) OP indicated his scenario was a self developed app he uses on his own personal device, not a hypothetical "friend". In terms of some unknown future scenario, speculative fear doesn't really provide anything in the ways of a constructive dialog.

2) In regards to inactive accounts, from Google's policy page:

>If you have never submitted an app for review and the account is more than one year old, it’s considered inactive.

>If you have apps, the account is considered inactive if it is more than one year old, all published apps have fewer than 1,000 combined lifetime installs, the required contact details are not verified, and you have not used Play Console in the last 180 days.

>Google sends warning emails at 60, 30, and 7 days before actual closure, allowing time to take corrective actions.

While you are correct that this would lose you access to the developer account, inactivity for a year and ignoring multiple warning messages over a 2 month period gives you an opportunity to weigh your options. It doesn't even require app updates, just activity in the Play console.