Why would/will I help him in his hard he did not help me in mine?

[thehammer]

Which one is correct?

1- Why would/will I help him in his hard he did not help me in mine?

And is there any other word for when/while?

 

[Tarheel]

You could argue that either is correct. However, see below.

Mary: Ron, Bob néeds your help.
Ron: Why should I help him with his hard time if he wouldn't help me with mine?

 

[emsr2d2]

@thehammer You have omitted a word after "hard".