- Offer to buy out the other owners so that you can stay on board.
- Make an offer to be bought out and leave.
- Bring a court proceeding and possibly dissolve the company.
If the company has a shareholders' or operating agreement that outlines the rights of owners, you should follow the procedures set out in the document.
If there is no written agreement, the only way to buy out or get bought out is to reach an agreement with your father. Yet, your description of him doesn't make him sound too agreeable.
At that point, your only recourse will be to bring a lawsuit in court to declare what you're entitled to and to value the company. Depending on the strength of the company, you may find that you could end up spending more in attorneys' fees than the value of your interest is worth.
It's best to consult with a local attorney know understands these issues to develop a strategy and get an estimate of the costs involved.