Yes, he would have to add oil to his car accordingly. Some people let the oil drain back into the block, but it usually has a tiny bit of fuel in it, which is not good for lubrication.
The valve cover breather IS a vent. I didn't say the oil from the PCV went into the valve cover. I said the oil from the PCV and valve cover stops in the catch can. That's why he has two filters on there. Lets excess fumes and pressure out of the catch can.
1992 Eagle Talon TSi - sold (POS)
2002 Mustang GT - sold
2002 SVTF - sold
2008.5 Mazdaspeed3 GT - cursed
2003 350Z Track - basically stock, and it runs