Legal Question in Civil Litigation in California

This is, unfortunately, true of some people. But uttering the words you mentioned will at best make you look bad, and at worst you could get sued, for example if the person really does themselves in.

If you do not say it to someone who clearly is about to kill themselves, it is not a violation of criminal law [so not illegal] and it is doubtful there would be any civil wrong [tort liability], but if you know the person is very depressed and your comments might be very harmful to them, you might open yourself up to suit [see the various cases in the papers about people on the internet driven to kill themselves]. But it is a stupid think to say to anyone.