I think he was going to Florida on this trip.
Actually, I65 is quite scenic and he shouldn't have any issues with mountain grades. It's just that I65/US231/I10 is going to be a longer trip vs I24/I75. Avoiding Atlanta is a plus, though.
Some facts about I65:
The welcome centers at the KY and AL state lines have been remodeled. There are no other rest areas on I65 in TN.
The first interstate segment built anywhere in TN was I65 from the AL line northward, 1.8 miles. It opened November 1958.
In April 2000, I65 was redesignated to the west side of downtown Nashville, replacing I265. The new route is about a mile longer, but the longer distance isn't readily noticeable because I40 mileposts are used where the two roads are multiplexed downtown.
One area to be aware of is the junction of I65 and I40 southbound just beyond Rosa Parks Ave. exit 85. The ramps are reversed from the normal configuration, and I40 west to Memphis is to the left, and continuing on I65 is to the right. The ramps then cross over. There have been quite a few accidents caused by drivers realizing they are on the wrong ramp and slamming on the brakes and swerving. I've even seen drivers backing up on the shoulder.