Not following. What do you mean? Will he not need to stay up late if "all are on GMT"?

I run my entire life in UTC and no daylight savings. All of my clocks and phones read UTC.

This makes no sense. Your morning meeting will be at 17:00 UTC (for example), but it will still be “morning” in the SV office, and “afternoon”/“multiple hours past sunset”/“go away I’m asleep” for your offshore team (wherever they may be located). Changing the digits our clocks represent will only simplify those clocks, but it won’t, it can’t, it shouldn’t change business hours to 9-17 UTC everywhere. Because why would half of the world sleep when it’s light outside? Just because Europeans set UTC as a time zone and 23 as the time to go to sleep?

Guess what. You're still going to have morning meetings relative to your local solar cycle and the offshore guys are still going to joining the call at a time that they're probably thinking about bed based on their local solar time.

Obligatory: https://qntm.org/abolish