"....would have to be done in a proper legal way like a loan with interest, a partnership or outright investment in RVX which would give them a percentage of ownership just like HL or the others...."

Even that would be inappropriate IMO. Directors and the board are legally required to act in the best interests of the corporation, be impartial, avoid conflicts of interest, and not allow decisions to be tainted by self-interest or self-dealing.  The above loan or partnership would fail on all counts IMO.  

Given the number of ways RVX has failed, no completely independent little biotech like Zenith would loan RVX money or invest in them.  Instead they would dole out the cash from a deal or buyout to shareholders (as DM has stated) and move their own internal programs forward.

Anyhow, RVX needs a solution in the next number of months.  Zenith will be unlikely to have any cash before 2025, at the earliest.