What is the best way to care for the nose when using an O2 machine?

My dad is 96 and uses an O2 machine. It goes through a water cup, but still drys out his nose. What is the best way to keep this from happening?

Well I don't know anyone that uses an O2 machine, so I can't say for sure, but here's some ideas.

Try heating the water a little bit. If it's through a tube and not a mask, try putting the tubes a little deeper into his nose. Try keeping his fluid levels up, the water you drink keeps your entire body from drying out. Maybe get a humidifier for the room?

Hope this helps.