Yes you can but there may be additional information needed. Your mortgage professional should be able to prove that this is an "arms length" transaction meaning the seller and the buyer are doing the negotiations and bargaining without one influencing directly the other party through blood relationship or extended degree of relationship, ie. this is not a sale within family members. The purchase and sale agreement needs to be crisp to get a mortgage that is not MLS. Also,. an appraisal may be needed especially if the price does not make sense.