There is a great deal of wonderful information here about doing this reading, and I think its appropriate to ask why does this person want to know about this?
There are some very 'real' things which maybe he could consider here, and find answers and awareness to, to bring some conclusion to this (his)situation - if thats what he is trying to do. He may need more of a basis (information - Spiritual, psychological) from which to see what has happened and why it happened, in a bigger framework - and this may not be connected to him - but moreson his friend who passed.
Was there anything he could have done - in the physical - NO - because it 'did not' eventuate that way - it is not so much the question, as it is veil to a deeper want of knowing more about the incident - the time prior to the person taking their life, and his part with in that timeframe, his actions and what he percieves as his inactions.
The primary thing is that the person 'has' passed. Regardless of the method in which the person died - he cannot bring the Soul back to physical manifestation, he cannot go back and 'physically' change the situation at this point. But he can and does, keep the energy 'alive' by thinking about it - and each thought, each probable senario he imagines and follows is as real and as alive as any physical action - in fact the thought proceeds the matter - so he maybe energizing the memory - the event - which will have consequences on another level - the event is 'still alive' and is being proceesed over and over within him.
Past present and future are not something seperate or linear, they occur simaltaneously, we percieve them as linear. The information you require from the past regarding his question, is as much here and now as it was 'back then'.
Although there may be answers relative to the way your friend feels - or about the friend which passed - I think, as to the question ... 'Is there anything he could have done' - the information does not need a tarot reading, that answer is already available. But there are other questions he may like to explore - possibly he has no understanding as of to 'why' - also why 'him' - why was he part this life experience - what was his role, his lesson, what wisdom does he gain from what happened, how has it and how is it impacting on his life and the decisions and choices he makes now which mould his future.
Compassion, understanding, acceptance and intergration. He may need to find peace with this complex issue within him through asking other deeper questions.
There is brilliant insight through the cards on what he needs to know - but the is also an infinite number of probabilities - the person's reasons may lie in another of their lives ... something may have happened during their birth, the reason may have been karmically contractual ... maybe he needs to know these types of things also.
I am feeling that your friend is burdened with blaming himself, or some heavy guilt. Im not sure how much your friend is aware of the actions that someone takes before commiting suicide, but there are behaviours which (by some who is 'seriously' considering committing suicide) which will push friends and family to the brink to push them away - and sometimes - after the fact, this becomes very obvious, it is part of the 'process and the thinking' of the suicidal person - moreso they can be come quite introvert and secretive so that others dont blame themselves feeling that there was something they could do.
The last thing a seriously suicidal person feels is that they want someone to 'do something to save them' - its a complication they cant afford - they are usually wracked with enough extreme emotional pain, loathing and helplessness, that an incomplete act is not an option - there would be too much to deal with - and their sights are usually on finality. In this case, it happened, and it is extremely distressing and confusing for those left behind. I think there is always that lingering question - 'was there something I could have done, some action, something more , something else'...and it is in hindsight, that these questions exist, and need answering.
So i go back to the original question ... why does this person want to know about this ... its a catalyst to the answers and greater awareness which are awaiting him.
just some thoughts on this
Blessings Elven x