It sounds like the 3 are tenants in common (or whatever the term your state uses), which means in this case that they each the percentage share of the property that you indicate. That gives them each the right to sell that share of the property to a third party. I just don’t see a stranger wanting to buy any share, except for very low dollars.
The 75% owners can buyout the 25% recalcitrant owner. In this case, it seems that will cost more than 25% of value. The 3 can also agree to sell the property and give the 25% owner more than 25% of the proceeds. The only other remedy is to offer to sell the 75% owner that share for a stated amount. If the parties cannot agree, then that the only other alternative is for the 75% owners to file suit seeking a court order to sell the property and split the proceeds according to ownership share.
I am presuming none of the 3 are currently living in the property, which would change dynamic greatly, and involve whether there a lease, what and how are the costs being shared, etc.