As far as a trailer blazer goes, I do recall selling one to a guy with a trailer blazer SS a few years ago. I think he was on here or pwctoday. See if he says anything.
I had a S10 blazer for about 7 years. The trailblazer is basically the exact same thing as the S10 blazer, but with a larger body and new trim. They both run the 4.3L vortec V6. The Trailblazer did come with a V8 but that's not very common.
The Trail blazer and the S10 blazer have very similar towing capacity, payload capacity and hitch ratings. They are very similar machines over all. You can expect the same results from your Trail Blazer as that I got from my S10 blazer.
The Trailblazer is basically a Colorado and the S10 blazer is bascially a S10 pickup. It runs a truck suspension and a truck frame. It is a truck. It has a truck hitch. It is a truck, but a small truck.
And as I said, it will kill the suspension. The back of the truck will be sagging after a few thousand miles. Mine suspension was wasted well before I sold my truck at 96k, and it had no sag when I got it at 36k miles. There's nothing to discuss or debate about his truck.
he is overloading it. Period. He will probably never break the hitch. He will probably always maintain control in normal driving conditions, but he most certainly will sag out his suspension. I would most certainly not use a hitch hauler AND pull a trailer at the same time with the trailblazer. I only want a hitch on my hitch hauler to tow my beach cart w/o removing the hauler. It very simply will not tolerate the weight without damage to the suspension.