Regarless of hitch used IMO that is WAY TO MUCH trailer for that 150 and I would really be concerned over the receiver load with that heavy 3P plus the dead tongue wt of the trailer itself I would bet he is seriously and even potentially DANGEROUSLY overloading his receiver.
No specfic wts. were given which really surprises me since I can't believe he isn't overloading something in the drivetrain like the rear tires or axle. I can easily believe a total tongue wt in the 1500+ range for his combo.
I am constantly amazed and confounded by folks that put this tow combos together and don't even bother to go to a scale and confirm just what they have going down the road. I guess this is another ignorance is bliss scenario and that too bad :S:h:S
Larry