a possible remedy :
a rather large aftermarket transmission cooler .
i am one of the "weight police crowd".
i tow a 21t komfort with a duramax .
i advocate every new vehicle purchase for towing a square box on wheels should be minimum , an f250 or 2500 pickup.
that said in my early years of towing starting with my first new car a C20 suburban with a 402 , i had an auxilliary automatic transmission cooler installed on my tow rig .
i added the aux. cooler to every rig ( 6 ) until i bought my new 1997 chev 2500 with the big block 7400 vortec / 4L80E.
the auxilliary tranny cooler does in fact lower the temperature shown on the coolant guage .
your acquaintance will be buying a real tow rig in a few years .
in the interim an aux. tranny cooler will keep the transmission from burning the fluid and then requiring a rebuild.