As 402(g) is an individual deferral limit, 415 is whose limit? employer? plan? employee?

Here's why I ask:

We have an employer with a profit sharing plan. Among their eligible employees is a person who owns his own business. In addition to the generous profit sharing contribution he will receive from his employer, this employee/business-owner would like to create for himself a uni 401(k)/mini 401(k) (a one-person, business-owner retirement plan).

He is eligible to receive a hefty profit sharing contribution from his employer. He is aware that he cannot defer in excess of the 402(g) limit for any given year, but is wondering if it is permissible to receive, in combination between his employer's plan and a uni/mini-401(k), in excess of $40,000 in profit sharing contributions (or whatever limit applies for a given year).

I have done some web searches and can't find anything that specifically addresses such a situation.

Thanks for guidance!

415 limits are applied in the aggregate to all plans maintained by an employer. Unrelated employers would have separate 415 limits.

So, to confirm, for example, this person may receive a total of $80,000 between the two separate plans?

Is there any chance these are not unrelated employers? Does the EE have any ownership (directly or indirectly) in the first employer?

I have a question regarding 415 limits for employees that participate in a single retirement plan maintained by more then one unrelated employer.

If the employee worked for two employers in this plan would the employee have two 415 limits?