No one is really right. A Buick with 133,000 miles on the clock and well maintained is expected to burn a quart every 3000-4000 or so. Nothing unusual about that.
On the other hand, starting a car in the morning with 10W40 oil will add to engine wear and INCREASE oil consumption. However, it will not cause sludging, and those two should know that. Sludging is caused by changing oil not often enough!
Last year I rented a new Toyota Matrix, which uses 5W20 oil! It also said in the manual that having to add a quart every 750 MILES!!! was not unususual. In other words, today’s thin oil lubricates OK, and activate the valve gear, but expect oil consumption. In your case, I would stick with a quality 5W30 oil and add as needed. It will mean the cost of a six pack of Budweiser every few months.
P.S. Both father and son need a basic course in the priciples of lubrication!!