Welcome, Ironsvx!! Join us often -- there's never a dull moment.
One of the way to defray possible costs in the future, since it is a "family" car, is to develop a fund where all family members contribute. There WILL be costs to consider -- all the same things one has to deal with with any car, however, parts will be a little more expensive.
I've had seals, belts, battery, you know, the standard stuff worked on. I've gone through transmission "hell." But I wouldn't trade this car for a buckload of new anythings!!! Of course, most people think I've become somewhat obsessed with this car, but, I look at it this way: Everybody needs a hobby. I don't play golf, I don't "collect" anything -- there are more and less expensive hobbies than having an SVX, but, it's the one I have chosen.
So, from your description, you *are* going to let your son drive the car every once in a while . . . right?