I'm sorry to hear that your friend is struggling. It's good at least that they are being honest with you about how they are feeling. I think that letting them know you are simply there is a big thing, and a positive thing for them. Being there for them to speak to will no doubt be hugely helpful as an outlet.
Hopefully they have people around them generally to speak to for support. You could also suggest resources such as Cruse. They have useful information online, as well as a helpline. Speaking to people from an organisation such as this can be helpful in terms of managing and processing grief.
Everyone's experience with grief is different, but I hope that your friend is able to find things more manageable soon, and that you feel able to support them where you can.
