re: How the frick can a non sitting president be impeached?

He can't. The US Constitution says, " The Chief Justice of SCOTUS must preside over the impeachment of POTUS."
J Roberts has already said he will NOT be there.
If he isn't there, no n-peachment can be conducted. No one else is allowed to preside.
This will be another fake n-peachment just like the fake Muller probe.