Is suicide ever rational?

No, this question is not about me. No, I’m not suicidal.

I have a very close friend who lives in another country. We chat and/or Skype every day. We’ve known each other for 11.5 years.

His life has been dismal for longer than we’ve known each other. He’s lived with chronic back pain that is treatable with only the highest doses of pain killers regularly available. Surgery hasn’t helped.

He’s had bad luck in relationships over and over again.

What’s perhaps most striking about him is his intelligence. He’s certified in the top 0.1% of Mensa.

He has a striking sense of humor, and indeed, he made a living for years as a stand-up comic.

But he’s now in a place where he’s truly stuck. I won’t go into the details, but he’s honestly in a place that seems hopeless. He’s in constant pain. He’s alone. He has no money.

Can suicide be a rational choice in some situations?