I had the same thought, but if it is a 1000 person company, that is large enough that the seniority level of their title is just as likely to be based on the compensation band of their HR structure as much as having any relevance to their actual skills.
Depends how rest of his career experience has been. He was an engineer and he has been a founder. If the product is technical it very well makes sense for me that he is well beyond junior or mid level depending on overall experience.
Not if the "founder" experience as a founder was micromanaging a startup of 10 people. I had a PM like that once and he was one of the worse PMs I've had.
I personally disliked being micromanaged. But even trying to leave personal feeling aside, I don't think he knew the team or the product well enough to micromanage the work effectively. It just made everybody more frustrated with him and work.
Well, maybe not everybody, but the others on the team that I talked with. As far as I know after only 9 months 75% of the team had been fired or left.
Founder implies wearing a lot of different hats all at once but also the power to make choices, including defining bureaucracy and processes. Senior PM implies a much more limited silo of skills but also limited powers and a need to be able to fit in with existing bureaucracy and processes.