[corvallis]

> and signing off very early to babysit his young children.

Are you serious with this? Parenting is not "babysitting". Would you call it babysitting if he wasn't a male parent? It's 2019. Both men and women work and share parenting responsibilities.

It sounds like you don't have these outside responsibilities or have delegated them out. However your general tone makes me skeptical about your maturity and objectivity. Your colleague may be in a wrong-fit job, or you may be irrationally funneling all your energy into comparing yourself to him and resenting him. Or somewhere in between. Or maybe there is another reason the founder has not addressed the issue (yet?) that may be none of your business (like having to document poor performance, or giving the guy a chance to find another job).

As others have said, it's just a job. Do your part and don't worry about him. And maybe find some hobbies to give you a reason to leave work and focus on other things. Or if you're that miserable, you are also free to find another job. No need to create drama like "me or him" ultimatums, just find one and give notice like an adult.