If anything, I think being a parent made him more focused, better at time management. Young, first-time founders tend to see "work more hours" as the solution to a lot of problems, even when the right answer is something else entirely. He was great at saying, "No, that isn't worth doing," or finding clever ways to solve problems. A lot of his product ideas came out of the time he spent after putting the kids to bed, and I think having the break plus the quiet time away from the office was great for his creativity.
It was also an advantage in recruiting. I could honestly tell engineers that we didn't believe in working stupid hours. And that engineers with kids would be able to have dinner with their families, because that's what the CEO did himself.
This thread is full of other people who have done similar things.
The problem I have with your comments about starting companies and parenting is not that it discourages new parents from considering starting a company, but that it once again posits that tech startup founders are an oppressed class. But consider raising a kid while working full time cleaning offices. Or as a construction worker. We sometimes sound like we actually believe that only the wealthy in this country successfully raise kids, but we obviously must know that isn't true at all.
[edited to depersonalize the response; sorry]