When you say "we all came in under founders common stock", you mean that you WILL all have founders common stock once the incorporation papers are signed, yes? You said above that they weren't signed yet?
Founders should always have vesting. It is going to permanently screw up your company if this guy has some large percentage of the company and isn't a part of its success. Plus the rest of you should have vesting anyway in case another founder doesn't work out for whatever reason. Everyone should ALWAYS have vesting.
So my advice is that, if you haven't yet signed the papers, you should go back and put vesting on all of the founder's shares, including his, of course.
Founders should always have vesting. It is going to permanently screw up your company if this guy has some large percentage of the company and isn't a part of its success. Plus the rest of you should have vesting anyway in case another founder doesn't work out for whatever reason. Everyone should ALWAYS have vesting.
So my advice is that, if you haven't yet signed the papers, you should go back and put vesting on all of the founder's shares, including his, of course.