Don't try to tell them it'll all be ok or that you understand. I can tell you that is not what they want to hear. They want to hear two words: "That sucks". That's it. Two words and a hug is all they need to feel a little bit better. Then this person knows you're a safe space and they can come to you.
2. Write Them a Note
You have no idea what a little note of encouragement can do for someone. A quick reminder that someone is on their team can make their day a little more bearable.
3. Give Them One of Their Favorite Foods
This might be their favorite candy or snack, or whatever this person likes. A small packet of m&m's left on their bed might be the one reminder they needed that day. Picking up something out of the dollar section at target or while you're on a quick CVS run shows your chronically ill friend that you still think about them and care. It's maybe two dollars that can brighten an entire week for someone. Worth it right?
4. Offer To Drive
Yes, sick people can drive too, and that handicap placard really is one of the only benefits of being ill, but it can also be so difficult. Offer to drive to dinner if you're going out with them. Maybe offer to pick them up or drop them off for a class that's too far for them.