Responding to Someone's Good News:
That's fantastic.
(I'm) really happy for you.
See? What did I tell you?
Look at you!
All that hard work, finally paid off.
Good things come to those who wait (idiom)

Responding to Someone's Bad News:
(Someone's passed away):
I'm really sorry to hear it.
What was the cause of death, if you don't mind me asking?
They're in a better place.
They're no longer in pain.

Responding to Someone Failing an Interview:
Their loss!
Get up, dust yourself off and try again (idiom)

To be mindful = to be careful