I technically have 3 jobs, two unrelated "full-time" SE roles, and 1 mom&pop store where I handle all but day-to-day operations (handled by the gf).
To be cold bloody honest, unless you are SE for a serie-A start-up a 40h weeks is probably 20h work, 20h bs. If you were SE for a serie-A start-up, a 40h week would probably be 80h-paid-20h anyway.
You mean to say that you are collecting two paychecks under the pretense of each company thinking you are working full time?
Even taking on a side job contract has IP issues. Most companies claim full ownership of any IP produced by employees at any time, on any devices.
There’s also workman’s comp and medical insurance, unemployment insurance and all other issues that conflict with multiple full time employment.
I know people that work full time and do a side gig. Either their own business or a part time under the table contract job.
I’ve never known anyone work multiple full time SE jobs. That leaves easily discoverable paper trail.
If, for example, he needed to decline health coverage at one employer he can simply say he has it through a partner. It will not be questioned. The workers comp and unemployment insurance won't matter. Multiple jobs are normal for many folks and the payroll companies and government won't care.