At least, for the US-side lawyers (I'm presuming Mozilla's US lawyers are on this one) due to conflict-of-interest rules, they would not be able to step in to offer advice and guidance to him directly, because the representation would probably be adverse to Mozilla's interests.

The rule in most states (based on the ABA model rules) is " A concurrent conflict of interest exists if: (1) the representation of one client will be directly adverse to another client; or (2) there is a significant risk that the representation of one or more clients will be materially limited by the lawyer's responsibilities to another client , a former client or a third person or by a personal interest of the lawyer."

Even if you don't believe #1 applies, #2 definitely applies.

Norway may have different rules, but the local Mozilla lawyers are bound by their local state bars, where this rule (or some variant) would apply. I've avoided discussion of whether this conflict could be consented to by him, etc, as it varies from state state

This of course, only applies directly. They can and probably are talking with his lawyers, just not advising him directly.