Does Red Leaf Lettuce contain Chlorophyll?!
Yes it does. Almost all leaves contain chlorophyll because plants need it to make their "food." If you look at red leaf lettuce, you can still see green around the edges. Of course it has a lot less than green lettuce; I don't know how allergic he is but it's probably not safe.
Most fruits and vegetables don't contain chlorophyll, though, and if you're not vegetarian I don't think you need leafy greens to survive. Just use more fruits and vegetables and different kinds, and also maybe some beans and nuts. I'm not familiar with the allergy but I'd assume you shouldn't feed him anything green; if you're really concerned, why don't you do some research?