Very true. As a poor second option, if he is working from known fixed IP locations, he could have used a packet filter to allow access only from them.

If he is roaming freely, he had no business leaving port 5900 world accessible.

All this micro-management of these standards only serves to confuse people and ultimately causes entry errors and wastes time. Go find the relevant XKCD comic on your own.

I personally miss the Plato IV Plasma Terminal Keyboard - https://codex.retro1.org/plato:tutor:plato_keyboard and http://xahlee.info/kbd/plato_iv_keyboard.html . Those keys on the right with represented many common functions. But the entire keyboard was designed for a future where computers would facilitate many worlds, not just a replacement for a typewriter or calculator.

My iMac Pro 2017 is an Energizer Bunny. I got almost 10 years from by MacBook Pro.