Should employers help employees with mental health issues? Yes, of course.
But it comes down to the individual supervisor to make something happen.
If someone has never been late to work late, and now they are coming to work late 3 days a week, something has happened. If someone now seems to have anger issues that weren't there before, something has happened.
This will make the culture and environment of your organization special. People will notice. People will talk about it. You will attract better people. You will get less turnover.
Some companies don't want to get involved. But you have no choice. Employees are people. People are going to have issues. You can ignore it, or you can embrace it and be there for people.
Pay attention. You can see it if you want to see it.
Get to know your people well. When someone changes, something has changed. Find out what it is. Give them access to resources and help they need. Let people know you care and you are committed to them.
Here is one thing I can promise, if you haven't had a tragedy, you will. And when you do, you will want to feel people care.
Start caring more. Even if it creates more work, care for the people around you.