If you find your friend not the same like before, ask them whether they are okay, talk to them and figure out what's going on in their mind. Your one moment of listening to them can help them release their anxious mind and will make them relieved from the pressure of the number of tabs open in their mind. Help them, listen to them, if they don't say anything just simply hug them and tell them that ‘everything is going to fine’. It's okay to have mental issues. Support such people and make sure they are alright.
As we celebrate mental health day today, lend your ears to listen and shoulder to cry to your loved ones to make them feel alright.