Subpoena them. If and when the Democrats vote for impeachment, Republicans in the House will gain the right to subpoena witnesses and documents. Right now, because there has been no formal vote, only Democrats have the power of the subpoena. Republicans can start by subpoenaing Biden – a spectacle that will end his presidential hopes once and for all.
The Russian-Republican Complex is trying its best to concoct a scandal regarding Joe Biden. This international complex has even devised what they believe will be an effective slogan to chant at Republican rallies regarding Joe Biden: "Lock him up!"
The right-wing media obsession with ginned-up fake scandals against Democratic opponents combined with extreme corruption and otherwise unethical behavior embedded the Republican party further combined with mainstream media's belief that fairness means creating an equivalence between the two is absolutely toxic. That's what produces this kind of advice. If we have to look back at our fallen democracy in retrospect, this is candidate #1 I'd bet on for why it happened.