But he got stuff done. I mean, middle of the night, when a server went down, he fixed it. I couldn't argue with that. Some people just do things on their own time.
But it has to work for you. If you're not cool with that kind of person, deal with it now, before you sign papers.
And it has to be a two-way street. This guy who worked for me let me know that he couldn't keep regular hours - it just wouldn't work. He didn't just stop coming in - he told me about it. We worked out something that would work.
If your guy is just missing stuff and not telling you, that's a trust thing.
Partnerships are marriages. You have to trust the other person. You are one. And it's way way easier to break up with your girlfriend/boyfriend than it is to divorce your spouse or dissolve a business partnership.
If it bugs you that much, deal with it now.