I think this is a wrong sentence since it has both future and present tense!!!! Is it correct??
I can see only one verb in that sentence: आयेगा (future tense). Where did you see the present tense?
I believe I understand your problem: "now" logically refers to the present (or the very near future) and "never" to some point between present and more or less remote future. One could say "Your son will not come now" or "Your son will never come" but "Your son will never come now" sounds awkward to me, too.
It's a pretty common phrasing, with 'now' used to mean 'given the existing conditions' rather than 'at this very second'. Eg. 'You've broken it. It'll never work now.' 'Your son will never come now that you've insulted his wife.'
Is anybody else putting home into the answer when it wasn't required or leaving home out when it was required?