Friends hi-fi system not very good, what do you do or say?

@whart 

Nice system you have there Bill.

Thanks, @ozzy62 . @grislybutter - I'm off the sauce but you can have a drink as long as you don't touch the turntable. :)

best to all, the one thing these hobbies/pursuits do in my experience is bring people of varied backgrounds together --when I was involved in auto sports I met a lot of interesting people as well. 

I became a bit of a hermit during Covid and actually enjoyed the quiet time. Now I'm making an effort to get out more and engage with others. I learn a lot from others about life experience. 

Far too many unknowns here to justfiy issuing "advice" on the system.

The friend may have a strong emotional attachment to the gear and would be hurt/devastated with negative comments.  "Hey, those are XYX speakers.  They sound great as long as you don't try to play music through them.  And, that (crusty) old receiver.  Not worth the postage that it took to send it over here from Japan."

One of my favorite church reader boards states: "A good friend stabs you in the front." So, with that "wisdom" in mind, you can just come straight at them with the "truth" related to all things negative about their system -- including the build quality and esthetics.

But seriously, your friend may have arrived a good point in their system in their estimation.  They may have moved past their interest (obsession?) with stereo and now spend their time (and money) in ways that are far more rewarding to them, and their families.  Snapping their attention back on the flaws and shortcomings of their system may be unwelcome (at the very least) could make you look like an inconsiderate ---t, an honor that may be well-deserved.

"Wow! I've never heard a system like this before!" Or, "truly remarkable" may be appropriate responses.  Best approach would be to listen to see if they indicate some issues with their system and ask for suggestions.  Otherwise, leave it alone and move on to the next opportunty(s) to bond with your friend.

OP, You didn't indicate if your friend wanted an opinion or not. If they merely turned it on for background music, case closed. Did your friend give any indication that they wanted your opinion? A few kind remarks could start a good conversation. Talk about music only. If your friend is interested at that point then continue. They may not give a hoot. Ask them if they spend any time in a good listening session. If the answer is "no". invite them to your house for a listen. If you get no spark then that's that.                   Where "audiophiles" are concerned, we should be prepared for criticism. It's part of the deal. Even unsolicited criticism. It only makes us better.

Key point as mentioned is if the friend asked for it desires your opinion on the sound.   If so then help if not then it’s non of your business really.   At least that is how I operate in similar scenarios.