Not really sure why. He should just let the GOP clown car run its course and then run as the sensible alternative to whichever fool they nominate. But I suppose this doesn't hurt. He's got a ton of money.
You can't take it with you. In the larger scheme of things $1 mill is not that much and it's probably a good thing to start building your narrative now. Besides with god knows how much money that will be spent on the senate race come Sept/Oct Pennsylvania airwaves will just be one big political commercial everyone tunes out.