UKPassats

Really struggling to find out why my brothers passat won't start, on Friday on his way to work the car began to misfire and judder with the engine management light coming on telling him to stop, like an idiot he thought it was the oil warning and put way to much oil in and carried on home. He managed to get home stopped the car and then it wouldn't start up again, it cranks but won't fire but it seems like the engine is cranking to slow to fire up. Plugged it on vcds and it says cam sensor low signal. Changed the sensor, coil packs battery and spark plugs but still the same also checked the fuses. Really stuck no and don't know what else to try, any advice anyone?