Have him wear heels. There's also an operation, in south Korea and other places, where the doctors go in, break your legs, put in extenders drilled into the bones and hey, a couple inches, if that, gained. Of course, make sure your son is fully grown first and consents to this. And it takes a year or more to heal and a lot of times, doesn't even work.
And how old is he? And why are you concerned about how tall he is?
Yeap be active and play sports an drink milk
Be active,drink milk,healthy food,vitamins,get enough time of sleep
yes , go back in a time machine and change his parents
so he has genetic difference or better gene pool
or you could invest in a medieval stretching rack
nothing you do will increase his height.
