Is this cactus sick?

[PinkPetalPolygon]

a friend of mine was given this cactus recently

does it look sick, or is all that crusty stuff normal?

what kind of lighting should it be getting, thanks!?

[ButterflyLady29]

Yes, but if it's just from being dry or sunburned I can't tell. The best thing would be to try propagating it from the healthy looking growth.
This site has some really good information, care as well as propagation techniques;
http://www.plantsrescue.com/tag/crab-cactus/
It's very similar to a Christmas cactus and requires the same care.