I'm not sure that Hikaru's parents don't try to be engaged... I always get the feeling that they support Hikaru doing what he wants to do, but for the most part just wander around confused; it must be quite difficult to rationalise seeing their son do a complete 180 over the course of a few years, especially when that change involves a very complex game that they barely understand, and, as you said, large monetary investments and a stunted education. It's hard to say how Masao feels, since he's almost never featured, but when Hikaru began the pro test, Mitsuko did mention that Masao was doing research on what "being a go pro" meant.

--akota