re: "Are there the rules which deny me to hire my friend, neighbor, relative via Upwork?"
You referenced the Upwork TOS document at /legal
The following general notes are NOT about the original poster and do not refer to any participant in this thread:
I can assure you that the countermeasures used by Upwork's Trust & Safety Team and by Upwork's automated algorithms are NOT necessarily documented in publicly posted TOS documents.
Punitive actions, including account termination, can indeed be taken without regard to the presence of explicit language in TOS which meets any individual freelancer's requirements.
In other words, it doesn't matter if Upwork never posts a rule stating you can't hired your brother. You still can't hire your brother, and Upwork can terminate your account if you do.