Looks like it suffered heavy pest damage.

Yes definitely. I see cabbage worms on then all time so I plan on doing row covers for them next year. However the white yellowing is an indication of a disease is it not?

Cabbage worms make holes. Lots of holes. The white, yellow, and brown is something else, though. I've seen leaves 50% eaten with no strange colors.

it seems to be spreading too. it started off on one plant and has been going through almost all of my collards

Not a disease. Leafminers.

You might want to look up "black rot". Major cabbage disease, and certainly will affect collards as well. Your pictures strongly resemble pictures of that online. It's a bacterial disease, and not easy to manage. It happens when the plant is wet a lot, and things get warm.

thank you dan and Jean. i checked out black rot and leaf miners

black rot indeed does look like the first stuff

anyone have any idea on what the second stuff is and more importantly if its harmful? im a bit scared of eating the stuff. at first i thought it was just some sort of off colored collard but as you can see in the pciture, it can be wiped off and just like the first disease, it seemds to be spreading as well

So the black rot is what I see in your first few pictures. What's the "second stuff"? You mean the eaten leaves? Probably cabbage worms. They bore holes in leaves. But what do you mean by "wiped off"? You mean in the last picture where part of the leaf is green, and the whitish coating is gone? That was wiped? Looks like powdery mildew. That's treatable. I wouldn't eat powdery mildew, but you can wipe if off, and kill the rest with hydrogen peroxide and vinegar.