He thought that Le Pen was going to win, so no he's not reliable, he's s delusional moron not worth paying the slightest bit of attention to.
Well to be fair, although I knew Macron would win I thought it would be way closer (say 55-45 for Macron), and at the time it didn't seem totally impossible Le Pen would win (although I figured she wouldn't). Source: I live here
The problem was that his "analysis" had zero statistical or scientific basis. It was just a rant about "muh immigration" and "muh EU". Which clearly weren't as relevant issues as he thought because if they were the first round would've been different.
After the first round it was pretty obvious Le Pen had no chance of winning the run off. She would've needed at least a third of the voters for leftist candidates.