Duplex options...give your advice!

Hey all! New user here. Looking to find some direction on this subject. My family bought a duplex years ago with a friend. 2 units 2 families, both head of families owners on the title. The one family wants to sell, mine however does not. The other family has a real estate agent that is giving us the option to buy the entire property. Is this only option? One real estate agent that I talked to said I may be able to refinance it that way I would owe the original value of the home and not the current value, I would like this option as the home has appreciated quite a bit and I wouldnt want to buy when it is high. Any advice is appreciated, thanks.

The refinancing works, but the agent isn’t making sense. You’d have to compensate them for current value of their half. That means you’d have to cash out on the refinance to buy them out or bring money to closing.

Yes she did mention having to pay them their money. I forgot to include this in the post.

I hate to buy out the other guy, rather sell and buy another house. That’s me.
The complication is how to compute his portion. Can’t be just 50% of market price because need to pay tax on capital gain, if he gets 50%, you’re the sucker. If the units are not of equal size, even worse.