I believe bravery in AFTA is dependent upon interpretation; as are virtually all topics; and so long as you can provide adequate evidence to support your contention, anything is possible.
Personally, I believe there are some core points of discussion
- Catherine's death, acknowledged as Hemingway's 'code hero'; brave in defeat, accepting and wanting to impose no burden on Frederic till the final moment - "don't worry darling, I am not a bit afraid"
- Frederic in his desertion of his comrades to escape with Catherine; may be interpreted as cowardice, however, he believes an escape is necessary if they are to embrace each other in ethereal serenity; the fanatical escape.
- Catherine escaping across the icy cold lake with a baby, their love and bond so strong enables them to escape
- Catherine eliciting no intention to get married immediately, brave in the midst of the controversy surrounding women who fell pregnant without being married
- The omnipresence of 'the dirty trick', a will to live on despite the reality of malevolent providence
- I'd imagine you could mention the bravery exhibited by the Priest, brave amongst nihilistic views and taunts by atheists, continues to embrace and rely upon religious (although he does eventually lose hope) - the quote "the world breaks everyone" and "If people bring so much courage to this world the world has to kill them to break them" - whilst primarily supporting the notion of individual futility throughout the corruption of a dire, desolate war; it also indicates how individuals lose fellow comrades, lovers and spiritual aspects - faith/religion.