Motor Carrier hiring Broker to cover loads due to truck shortage

My brother in law owns a trucking company with 8 trucks (Hot shot) and has a customer that needed 10 truck loads moved. I work for a broker and he wants me to cover the 2 loads he cannot. He does not want the client to call someone else as this is his primary customer and does not want them to feel he cannot cover the loads. He will hire me to get a truck to cover the loads and he will be my customer. My supervisor said this is legal but our co-worker claims it is not. We looked it up and could not get a solid answer as I feel this is not double brokered but nor is it interlining... any thoughts.

 

what do you mean cutting the rate? He said we could only charge him x amount so I would more than likely post this amount minus our % for broker... in this case 10%... i.e, He said $100 max charge we would then post on board for $90.00