Considering the air supply, I'd dump the candles and replace whatever lights you have with low wattage LED's. Candles will literally burn up your air supply. LED's will allow the batteries to last much longer.

I'm assuming the shelter design in the video is more generic than specific to your friend's bunker. If it is just like that with the above ground structures, armored hatch and air vents, very cool.

Were I to have a nice deep fallout shelter, I'd build a greenhouse over it and install an air filter and a small air pump to ensure a good air supply to the bunker during a possibly long period underground. Since there might be an EMP associated with whatever I intended to shelter against, I'd have a couple solar panels in the bunker which would be brought to the surface after the EMP threat passed and would be used to keep the batteries charged, air flowing and lights on. With an EMP in mind I might even consider taking the shelter/greenhouse off-grid so that street power/grid electricity didn't destroy the electric system which would kill the lights and turn off the air. But that's just me thinking without seeing the layout of the subject bunker -- where it's located relative to London or other juicy targets. Worth about $.02 or less...