Will he be motivated enough to use it more than a few times before it becomes a valet for clothes and jackets hung on the bars?

I just can't motivate myself to use them often enough, though I have both a very old stationary bike and a very basic wheel on trainer. Sometimes watching bike races, like cyclocross or the various tours and monuments take my mind off the boredom of pedaling to nowhere. But not enough to get me on either regularly.

Rouvy or Zwift might make it more interesting. And obviously for many, it does. So maybe consider at least a trainer that can make effective use of those virtual worlds if it's found out the incentive is needed.