Of course often when the amounts involved are relatively* small (*depends on the venture and the people involved), sometimes the costs that one co-founder incurs is handled in an informal way, and is part of the relatively even contribution between co-founders. Partnerships are never equal (contributory aspect) all of the time anyway. Sometimes you pull more weight, sometimes it's the other(s), maybe it never evens out -- but if it's close enough it's a better working dynamic to leave it simple.
if the guy gave you the $ and wanted 100% you would not do it and you would jump on it at 0%. The reality is somewhere in the middle.
Needless to say, the situation didn't end up working out very well. YMMV.
1. First Vesting. Always vesting. 2. Second Vesting. Always vesting. 3. Do not do preferred for a small round. The legal costs for preferred are high >20-30k 4. Do common. Can be done in less that 5k 5. You could consider what Y combinator offers and tee of that (20k,60%, very valuable connections)
5.
Good luck with this.