CFII Loses Medical

I'm roughly 15 hours into my Instrument training, with a friend who is a
former Eastern and Kiwi pilot. Yesterday he had triple bypass surgery. We
discussed what to do, since I would like to continue my training with him.
We seem to be very compatible.

As far as either of us can tell from the FARs, little has changed except
that he can no longer serve as PIC, which means that I will need to fly with
someone else in IMC. However, it is not completely clear about simulated
instrument conditions. Sec. 91.109 states that:

"No person may operate a civil aircraft in simulated instrument
flight unless--
(1) The other control seat is occupied by a safety pilot who
possesses at least a private pilot certificate with category and class
ratings appropriate to the aircraft being flown."

No mention is made as to whether or not that "possessed" certificate needs
to be current. Furthermore we can find nothing elsewhere in the regulations
about this. Any thoughts? Can I fly with my foggles on, with Ken in the
right seat?

--
Bob (Chief Pilot, White Knuckle Airways)