First Thing

Remind yourself that we cannot control the outcome in these situations no matter how sincerely we wish we could

Fully realising this to begin with, means taking a deep breath and quietly affirming in your heart that this is indeed the simple truth. This stops you concentrating on all that can't be done, all that isn't fair etc. and allows you to put your full focus on what you can do

Second thing

Remind yourself how it is also true that the outcome is not certain either way

A full and complete recovery may happen whether this feels like a miracle or not. So trust calmly that it can most certainly be the outcome

Third thing

Ask your heart calmly what you can do to best support this outcome in terms of emotional support etc...

Realise there will be times when you are holding a space for tears and sorrow. Decide you are ready empathically and quietly to hold this space for them when needed. Once you do this, any natural response you have in such a space will come purely from the heart - letting them know you are fully present with them at this time
Remember they do not expect you to provide any answers for them here. They require simply that you are willing to hold a safe space and remain present to all the pain and sorrow they feel the need to share. Believe me it is a tremendous blessing for them to have someone close, willing to stay fully present and genuinely warmhearted for them in this way

Fourth thing

but remember too that the best way to promote a positive outcome overall, lies in keeping the athmosphere light hearted between you most of the time

This is not in any way designed to avoid the sorrowful moments but to balance and indeed banish them after they come up and pass through. So, gently return to lightheartedness again after a reflective pause. Your friend will get a great lift from this flip side especially as it is all too easy to constantly feel emotionally weighed down and powerless given the circumstances. It will also benefit you too lifting both your spirits together

and finally

Here are some practical ideas for you regarding all this...

1 make a mental list...take time to recall funny upbeat situations, instances etc that you two have shared together and make a mental list of them, so that when you need to lift the athmosphere you can mention one of these to shift things to this lighter level
2 surprise them... the odd time give them an unexpected little gift such as a small stone, a cute fridge magnet etc .. just the occasional surprise of a little something that makes them smile
3 remind them... reflect with them on how situations like this one serve to remind us of just how precious we are to eachother. How precious every day is and how much you love them to little bits
4 take care of yourself too... be sure to look after yourself in all this. Seek out whatever support you need for you, professionally or otherwise, so you can keep your own energy up and your own spirits high, remaining strong for whatever is to come