What is the overall theme in the books " The English Patient" by Micheal Ondaatje and "A Farewell to Arms" by Ernest Hemingway"?

I think that that both works'  themes are different.  If
one can find similar in the thematic applications of both works, it might be that both
depict how wars change individuals and force them to be different than they might
originally have acted.  The wars feature changes both protagonists significantly. 
However, I think that this is where the similarities end.  Ondaatje is driven to show
that complex human emotions are rendered even more challenging in situations where wars
between nations put everything under a different prism.  Almasy is a protagonist who
seeks to transcend boundaries or national identity, yet is captive to them.  He is not
the Hemingway hero like Frederic is, reflecting grace under pressure and a sense of
accomplishment to his freedom.  Frederic’s depiction is one where evolution and change
are part of the ethic that Hemingway creates for his hero.  Even when Frederic suffers,
he understands what is important to him and a sense of completeness emerges.   This
isn’t Almasy, a sad figure whose freedom is used, but ultimately in a futile manner. 
Another significant difference that precludes me from finding thematic similarity is
that Hemingway is committed to the idea of being able to articulate a “real man” and how
that can overcome political strife.  Essentially, human freedom is shown in Hemingway’s
world to be something that might not always succeed, but is always there and that
individuals can take solace in being able to use their freedom in all conditions. 
Ondaatje is not certain of such a reality.  Nearly all of the characters in his work
have freedom and use it, but these exercises of autonomy are completely challenged by
the political reality and social conditions that undercut such expressions.  At best,
one can see Hanna as the female Hemingway hero as one who knows she is cursed, but will
endure on to see if it can be lifted at some point.  The fact that we would point to her
as a type of Hemingway hero might also be reflective of how divergent these works are in
the nature of human freedom and how it is shown in each.