According to the post, neither of them have vested shares:

> We signed a founders agreement, we each have a seat on the board, and he holds a majority of shares. None of our shares have vested - my first vesting date is in 6 months when ¼ of my shares vest.

Unvested shares are still shares. All that being unvested means is that the shares are subject to conditions such as a repurchase option that gives the company a right to buy your shares if you leave the company.

Unvested shares still have the others rights of shares, such as voting and sharing in dividends.

Vesting is just receiving the full rights of the share, option, or whatever over a specific amount of time.

If you start a company with someone you don't (er, shouldn't) just automatically get 50% of the company. That would allow you walk on day 3 and still own 50%. Instead you receive the ability to leave with your shares on a vesting schedule so that you have skin in the game.