How can I get my step-son his EB-5 visa without the consent of his biological father?

I am an EB-5 applicant. My petition includes me, my wife, and two kids. The oldest one is my step-son. Recently, we had an immigration interview in Warsaw, where we live. The consul told us that we need to have consent from the biological father of my son for his relocation to the U.S., and send the scan by email. They told us they will keep our passports and issue the visas once they get the consent. The biological father told us he is ready to provide the consent if we buy a $250k apartment in his name for him to rent out. If we collect all the evidence that he is trying to “sell” his consent for his son to move to the U.S., will it be considered a case where the consul could approve the issuing of the immigration visa based on the fact of abusing our child? Does his offering to sign if we purchase him this property count as consent with a contingency? What are our chances of getting a visa for my step-son without the consent?