Sounds a bit silly to me, if that really is his reasoning. Sure, there's a correlation between VO2 max and marathon performance, but a high aerobic capacity won't be enough to sustain a strong pace when the quads and calves start fatiguing at 22 miles. I suppose it depends what he's doing in the gym but I would've thought running lots of miles and then a few more, before tapering, would be his best bet??
Just to say that my above mentioned regime has gone well and with just over 4 wks to go all is on track for target time. I've stuck to my S&C' plan and have benefitted with sustained pace and stamina on long runs as a result of a cut back on 'midweek' mileage. Endurance has been a problem in the past and I'm on the way to cracking this. Regarding gym work there has been emphasis on leg strength and power which in the past I have tried to improve by more hill runs and intervals. I've definitely felt that less pounding on the legs have helped come the LR's. Each to their own I guess, proof will be there or not on Apr 21 st.