If you only show the 5%, prepare to respond to the IRS matching notice which will want tax, interest, and substantial underpayment penalty on the other 95%

Sounds like he's more a broker than a dispatcher.  If the load pays $5,000 and he collects $250, which amount is shown on the 1099?  Unless he's collecting all $5,000 and then paying the owner/operator, he should just be reporting commissions.  

So you want to just report the net 5% the client keeps instead of reporting the Gross receipts and expenses that net to his 5%  - Why????     You say the client issued 1099s but you don't want to list this on the tax return??     

With limited knowledge, sounds like the client should have sent 1099's out to the truckers he was paying.  Should be picking up the gross from the 1099's issued to him and deducting the payments to the subcontractors.