If you have a boy, which parent his height going to be inherited from?

Both. A way to predict the final height is take the average of the two parents' heights and add 5 CM for boys, subtract 5 CM for girls. This is, of course, very approximate.
Both. Since both parents contribute genetic material to the child, the eventual height includes factors from both. Although health problems may interfere with growth and some will be exceptional, there are general expectations based on parental height. Add 5 in to moms height & average that with dads to predict males. Subtract 5 from dad & average with mom for girls.