Congress has the power to charge treason but they must be convicted in order to be punished. In my opinion this should be where they are going with this.
I'm reading up on the Treason Clause and this is pretty straightforward but if there is a conviction it pretty much destroys Trump and his entire family.
"The Constitution also narrowed the scope of punishment for treason as compared to English common law. The final clause of this Section establishes that, while Congress has the general power to establish the penalties for committing treason, Congress may not “work corruption of blood, or forfeiture except during the life of the person” convicted of treason. “Corruption of blood” is a reference to English common law, which prohibited family members from—among other things—receiving or inheriting property from a person convicted of treason. Under the Constitution, that punishment may not extend beyond the life of the person convicted of treason."
Here is a link-
https://constitutioncenter.org/interactive-constitution/interpretation/article-iii/clauses/39