Yes. A spouse admitted in E-2 dependent status is employment-authorized incident to that status, evidenced by the spouse annotation on Form I-94, and may work for any employer or himself. Children under 21 may study but may not work.
The spouse can work in the trade, the company or anywhere else
The E-2 spouse rule is broad. Renata's husband would not need a separate employment authorization document; the annotated Form I-94 issued on admission is sufficient evidence for an employer. He could join the electrical company's office, take unrelated employment or start his own business.
His nationality does not matter for dependent status, so if he is a Canadian permanent resident rather than a citizen he still qualifies as her spouse. Unmarried children under 21 may attend school and may not work, and a child who reaches 21 must obtain an independent status. Because E-2 is granted in periods that are renewed as long as the enterprise continues to qualify, the family's presence in the United States can last for years, but it is not permanent residence and does not lead to it by itself.
If Renata and her husband hope to settle permanently, that is a separate conversation with a licensed U.S. immigration attorney about which employment or family routes, if any, could apply.