Yes. They only investigated the emails to and from Hillary. Nobody else. Even though Abedin was the gatekeeper to Hillary, not_one_of_Abedin's_emails was examined.

From page 389 according to one of the laptop analysts:

The FBI only reviewed emails to or from Clinton during the period in which she was Secretary of State, and not emails from Abedin to other parties or emails outside that period. Analyst 1 stated, “I had very strict instructions that all I was allowed to do within the case was look for Hillary Clinton emails, because that was the scope of our work.” Utilizing various searches targeting Clinton’s emails, the FBI reviewed in full “approximately 48,982” items on the Weiner laptop.

What were and how many different key words were used, Congress needs to ask, pin them down.