Everyone you know will experience a loss, death, or crisis in their life at one point or another. You absolutely will go through the same thing as well. So when you have a friend experiencing a big drastic sad change in their lives, remember to think through how you would want them to react to you, in the same situation.
Use the connection you already have.
The great thing about friendship is that you build a really strong connection to somebody. Use this connection to tailor your response. Some friends are really going to appreciate you writing a card and making meals. Other friends are going to appreciate you saying "hey, I know you're going through something that sounds really tough. I am happy to talk with you about that, or I'm also happy to take you out to dinner and not talk about it at all."
Don't "should" on them.
Most importantly, don't tell your friends how they should be feeling. And by that I mean, try and avoid saying things like, "You must be so sad right now." Or, "You must be so upset."
They might be experiencing their grief or loss differently than you would. Instead, let them take the lead. Sometimes people just want to hear "I've been thinking about what you're going through," and they'll take it from there.
Looking for other resources.
Some friends really do need to be connected with other supports, outside of your friendship. If you feel like you're taking on too much responsibility, or if they're leaning on you so much that you are starting to feel overwhelmed, help them identify others to go to.
Highschools and colleges have counselors available specifically to talk about grief and loss.
Or, if they're interested in keeping school and grief separate, you can find different counselor or therapists who specialize in grief issues through websites like psychology today.
Finally, if you notice your friend is maybe starting to experience a really low mood, engaging in self-harm after the loss, or experiencing suicidal ideation, connect them with a crisis line (such as the suicide prevention hotline, teen line, or even consider having them evaluated by a hospital if it seems very severe.
If you have a friend going through a loss, or if you're going through one yourself, counseling can be a helpful next step. Kelsey specializes in anxiety and anger management for kids and teens from age 4 through college, and has an extensive background in working with trauma, grief, and loss. You can reach her to hear more about her practice at firstname.lastname@example.org. Kelsey's office is located in Webster Groves, MO and she works with teens and college students from all over the St. Louis, MO area.