I'm not sure how anyone would think Biden purposely carved an exemption out for Congress. If he could have mandated it for them, he would have.
https://www.usatoday.com/story/news/factcheck/2021/09/20/fact-check-biden-cant-mandate-vaccines-congress/8384930002/
And there isn't anyone's family who is being required to be vaccinated with any of this federal mandate stuff that I'm aware of, so I'm not sure why you bring that up.