his might also explain why he think it's cool to write BSDM scenes featuring a 16-year-old schoolgirl as part of an ostensibly respectable work of SF, so it's a pet suspicion of mine.

It would seem he is just writing for Mature Audiences. In this case maturity means not just 'the age at which we let people read pornographic text' but the kind of maturity that allows people to look beyond their own cultural prejudices.

16 is old. Not old enough according to our culture but there is no reason we should expect a fictional time-distant culture to have our particular moral or legal prescriptions. It wouldn't be all that surprising if someone from an actual future time to, when reading the work, scoff at how prudish a culture would have to be to consider sexualised portrayals of women that age to be taboo!

Mind you I do see how a hypoxic brain injury could alter someone's moral inhibitions and sensibilities in the kind of way you suggest. I just don't include loaded language in the speculation.