I'll be surprised if Bond's parents feature, even in flashback, in the next film. They are not a part of how "Bond became Bond" in the way that Bruce Wayne's parents were in the Batman stories. Bond didn't wind up in the British SIS because of his parent's deaths, tragic though they were - as an orphan he could have gone into some other line of work, it just happened that, supposedly, MI6 in the Fleming/Bond universe has a tendency to recruit orphans. Wayne, on the other hand was deeply affected by his parents' murders and we know how that turned out for him later.
Bond's family featured in the second part of SF in passing references - another tenuous link with the novel You Only Live Twice, where we learn of Bond's family background via a rather premature obituary. But friends of mine who saw SF didn't even realise what Bond's family background was until then, and I doubt it would be that important to a general audience.
No - I think they're probably going to Austria because it forms a backdrop to the main story. Unless, that is, there's another borrowing from Fleming - a reference not only to Andrew and Monique Bond's accident, but also to Hannes Oberhauser, the guide killed in the short story Octopussy who was a father figure for Bond. He's not mentioned in the film OP - the stolen gold events related by Bond took place in Korea - but he could crop up here, if only to provide another tenuous link to the Bond sources material. Clutching at straws, I know.