I just heard my friend's father had a serious accident and

I had a similar thing happened to me. The best thing to do is not bring it up with him/her but comfort him/her if they bring it up. Just dont risk offending them or upsetting them by striking up the conversation with them yourself

>>17176733
"I just heard about your father. Is there anything I can do? If you have to go to him, I could pick up your homework/hand in your assignments/take notes/cover your part time job. If not, I'm a good listener if you want to talk about it."

>>17176733
Bro, I'm sorry about your dad. Here if you need to talk.

Alternatively...

"At least it will be cheaper to buy slippers for christmas now"

Ask him if he needs a hand.

>>17177839
There are a tonne of leg related puns you could have gone for and you got the fucking limb wrong. Fuck you.

>>17176733

"That's crazy, is he gonna be okay?"
"Sorry to hear that man. Prosthetics have gotten great though, once he gets the hang of walking on it he's gonna be okay."

Be concerned but encouraging