Post belongs to Post Holdings, which is publicly traded. Folgers is a subsidiary of Proctor & Gamble, and Jimmy Dean is a subsidiary of Tyson Foods. It seems unlikely that all three companies would even support their products being hocked together in such a manner. I wouldn’t be surprised if this was unauthorized and he’s attempting to appear like he has more support than he really does.
Edit: spotted Maxwell House in there too, and that’s owned by yet another company, Kraft Heinz.
Edit 2: Ah, it appears he wasn’t hocking these products after all. Apparently we don’t have to start foraging our own food yet.
He can’t, as this is an ideological split between the parties and would need to go through the house as well, where it would fail. Bringing this up now helps inform voters of an issue that could be resolved if Democrats turn out and take control of the house while retaining control of the Senate and executive branch.