If the investor believes that the potential market value of the patent holder's patent is very large, and the investor is willing to let the patentee hold more shares, then 70 is not too outrageous.
Whether or not to participate in management is decided by negotiation between the two parties. Usually, if you do not participate in management, the proportion of shares will definitely be reduced. After all, your income must be guaranteed by the other party, and they will not work for you in vain.