Cook’s stock in trade is Congressional elections and lower. This is because he tracks precinct returns and has done this for over 50 years. He definitely got the President election wrong in 2016, but so did everyone else, too. Take a look at his results for the House. He correctly called all House seats rated leaning and above. He didn’t make a call in toss up races. Chart at here: https://en.wikipedia.org/wiki/United_States_House_of_Representatives_elections,_2016
Remember that the Dems gained 6 seats in the House in 2016.
I learned not to bet with him years ago and won’t do it this year. The article is Oct 5, my guess that his numbers are lower for GOP losses today. My guess is 12 - 15 seats in the House flipping to the Dems, Charlie will probably have about twice as many. The current trends are encouraging, I think that the Dems have seen their high water mark.
Democrats always look good at the beginning of Oct. GOP begins to spend money in the middle of Oct.