Can you buy a house with BTC? Yes! All you need is a buyer with coins and a seller that will accept them. The value of the transaction is as of the date of the contract, when the coins change hands.
If the cases are the same and they are both using bitcoin and they also know about cryptocurrency nothing trouble happens. It is the easiest way of buying bigger amount of thing . Make it sure that you check the person if it is legit and trustworthy.