Revocation of a condition subsequent Gift

I had gifted 9 hectares of land to my son P on the express condition that he must construct a residential house for all my grandchildren on it within two years. He died within six months without starting construction. The deed stated that if this condition failed, the land would go to my nephew An. But I never intended it to go to An or to P’s heirs if no house was built. Since the condition was not fulfilled, was I not right in cancelling the gift and giving the land to T instead? Help me argue