It is never easy dealing with grief.
I know when we hear the words loss and grief we often relate them to death. It doesn't always necessary have to be death though.
1. Be a good listener
It's can be quite difficult to give advice to someone when you haven't experienced what they are going through but you can be there for them. Part of being a good friend and being there for someone is the ability to listen. Let your friend know that you are there for them and they can come to you. Simply be there to listen to them vent. It goes a long way.
2. Reach out to them
When someone is going through a tough time it can be easy to become a loner. They began to grieve and they no longer want to go out and have fun because they are constantly feeling bad. Ask them to hang out or to come over, even if you are getting rejected each time, keep doing it. Keep reaching out to let them know you are thinking of them. They will thank you for it in the long run.
3. Don't be pushy
When someone has experienced some type of loss they may or may not want to disclose of how they are feeling or what happened. Sometimes people don't want to talk about their problems or they're just not ready to disclose. Don't push the conversation. Give them their space and when they are ready they will reach out to you.