How curable is squamous carcinoma of the eye?

My grandpa has been diagnosed with squamous carcinoma on his eye. So there a tumor on his eyeball. He's going to the optometrist or something to get it surgically removed. I was wondering if it's a very curable cancer or if it's a more incurable type. He probably got it because he works at a golf course, so he's in the sun a lot. Is this something I should be worried about or not?