There's a lot of (valid) advice going around to check in with your friends right now.
I'll let you in on a secret: that person who always checks in with you to make sure that you're okay? Odds are high that no one is checking in with them.
Your "strong friend", the one you lean on, needs support, too.
We truly never know what other people are going through. Don't assume you know which of your friends are vulnerable or hurting. Check in on all your people.