I'm going with the hands-off descent...trim for Vg. Or how about a 1 minute turn (no clock/watch?) to get out of what he's gotten into. Altimeter and VSI to hold the turn level. Or has the pitot and static port iced over as well? Since there's no instrumentation, can't look at the compass, and I'm ATC, give him a no-gyro letdown...now I guess you'll tell me there's no xponder and I can't identify him on primary.
After it's all said and done, the CAA needs to yank the instructor's certificate for signing off a solo outside of the pattern without having given minimal hood-time instruction, 180 degree turn for inadvertent IMC, and less than stellar instruction on decision-making (continued VFR into IMC, continued flight with multiple flight instrument failures). They probably need to haul the operator in as well based on the condition of the aircraft. Preferrably immediately, but probably after the memorial service.