Basically what he is saying is that he doesn't want his life to change just because he lost a limb. He will do everything in his power to maintain his life. Examples: I don't have much money. I will not spend more than I need to on a new stove. Not if I can help it ( that is: I will avoid it) Mother to son: you will not be an artist, not if I can help it. Artists don't make enough money. ( She will try to stop him from becoming one)

Thank you, ladies! Actually, "more than I can help" looks for me like "more than I can make or afford", "that is beyond my abilities". But I gess, it's a sort of weird English idioms one has to accept happy-go-lucky :)

The loss of the foot wasn't going to change his lifestyle more than he could stop it (help it), ( more than he could stop it, to not let it happen). So he could stop it in some level (he could stop the process of the loss of the foot changing his lifestyle in some level) . So it was not going to change his lifestyle More Than The Level he could stop it.

Hi Igor. The way I read this, the soldier is saying that he is not going to allow himself to be victimized by his prothesis. The author is making the loss of the foot into a subject and he is saying "I'm not going to let you bother me... "not if I can help it", which is a common way of saying "I'll be darned if I'm going to let you bother me" or, "to the extent that I can prevent it, I will", or, more simply "I am absolutely not going to let you bother me". Another idiomatic expression in English for this is "Over my dead body!" Which is a strong way of saying "I will not let you do this thing to me". I hope this is helpful!