Belarus authorities don't give a fk on such request.
This is not Belarus authority. This is private company, which offers outsourcing services for USA companies. In this case, if they do not wish to lose business, it will be better for them to cooperate with USA authorities. This is completely about business reputation. Business reputation is vital and most valuable resource.
Firm is located in Belarus so it is under Belarus authorities. Thought if investigation will take place and finds firm suspicious, he will get arrest order issued by Europol. Means if he travels to EU he will get arrested. That is the only scenario.
As for the reputation, you are very correct.