My friend's dad had a stroke two weeks ago. Today I asked about his recovery and my friend said he is ok for now. I want to say that I'm really glad that my friend's dad is feeling better. Does "I'm really happy to hear that" sound natural to a native speaker's ear? What would you say in that situation? Thanks a lot in advance!
If you are genuinely feeling a wave of elation as you say those words to your friend then yes. However I doubt that is the case and the sentence seems overstated to me.
I imagine that your emotion when you hear of your friend's father is more relief than actual happiness. If you want to ensure your words are understood as being sincere I would be a little more formal, even with a close friend. Therefore I would suggest using "very" instead of "really" and "glad" or "relieved" instead of "happy".