[PaulRobinson]

You need time off. You need surgery and recovery time, and then you need some more time off post-recovery.

I say this as somebody who has recently returned to work after 2 months away due to surgery and needing rehabilitation post-surgery that was very intensive. I'm still feeling burned out, and I'm hoping to take a couple of weeks out in a month or two to just regroup and gather my energy back.

You need to figure out whether you can take some time out before making a decision, or if you need to make the decision now and then take the time off. If the acquiring company won't let you have enough time off (or more depending on the surgery), well, that's a problem, and you need to talk to your co-founder about whether you can do it whilst in the company.

The absolute top priority in all of this is your health: you can't pivot, sell or work for somebody else if you're not well. Deal with the burn out and surgery as an urgent priority, everything else is secondary.