I think your HB is a good person, even he is good to his friend, and you as a mother, as a wife, don't try your self as a baby. The solution is that asking this couple to invite U and your HB to have dinner, you will resolve your nail in your heart.
Actually, if this is the fact, the timing for negotiation with C fu is very important so as to settle the dispute. My experience in construction industry is that the C fu is thieft, but they will not claim the person in the same trade, so if your HB has experience on this matter, he will be a right person to help for settlement.