It's certainly possible. But federal judges, and especially SCOTUS justices, should be completely above reproach. At the very least, he should have to recuse himself whenever GT is before the Court. And I think they should be bound by ethics requirements that would require him to know who the buyer is in a deal like this and, if it could even possibly foreseeably lead to an appearance of impropriety, find another buyer.
With respect to the new reporting about how much John Roberts' wife made steering attorneys to elite law firms, there should be similar rules. Frankly, I don't think he should be able to serve on the Court at all as long as his wife is doing that shit.
Is that unfair? I don't give a shit. If you don't want your personal finances to be combed over, if you want your spouse to be able to work whatever job she wants without raising these issues in public, don't take the fucking job.