Didn’t someone try to disqualify Dick Cheney in 1992 claiming he was really a resident of Texas, not Wyoming, and therefore ineligible to serve as VP since Constitution says Pres and VP must be residents/citizens of different States? I am sure this happened and think he defended in the same way.
There are lots of tactical ways to fight a lawsuit. Sometimes it is advantageous to move to dismiss rather than respond to the claim.
This is a 17 state event, so far. He's spent 800,000. It indicates a tendency to waste money and a contempt for the electorate. What's the advantage in that.
IIRC he was residing in Texas, but still had a claim in Wyoming. Willing to hear information to the contrary.