I agree with Zentrode here his advice is quite genuine.
Personally I would do the exact same as what he said, ensure her that you are there for her and generally back off afterwards. If she needs some company then don't be scared to give it to her, do not fear the friendship zone either it isn't something to genuinely fear. Do what you would naturally do, there's no point in worrying about some friend zone when you can simply break that off by breaking rapport.
I sympathise with her as much as you do man, I think we all know what it's like to lose someone and whether we end up in the friend zone or not, it's great to know that there's someone there to help us.
Happy Gaming

AFCCoffee