My Mom is 89; her right eye swells and when she wakes up she has excessive crustacean in her eye. is this common?

You want to be VERY careful with crustaceans near the eyes, make sure the claws are securely rubber banded closed, or some ill-tempered crawdad could blind her!

No, this is not common. Your mother could have an eye infection and need medication for it. Take her to the eye doctor to find out for sure. My mother was having a problem like this and her eye doctor told us to get these over-the-counter cleansing wipes for the eyes.
Does your mom have any eye conditions that she has to use eye drops for? If the medication dropper gets contaminated or dirty it can cause eye infections.

Minor eye infections are common, and so are small foreign bodies (although perhaps not crustaceans) potentially causing them. Ask a doctor to examine her.

Ditto to possible infection (pink eye? conjuntivitis? chalazion?) so I would get her checked.

Sounds like an infection, I'd get it looked at.