Nice!
So for his test, after he has accepted the WikiTree terms and privacy policy to become at least Family Member here, your son can enter on his WiiTree profile that he did the FTDNA yDNA test, at the 67 marker level, his FTDNA kit#, and the Y-Chromosome haplogroup that he gets assigned to from the results.
For your test, you can enter on your profile that you did the FTDNA mtDNA (full) test, your FTDNA kit#, and the Mitochondrial haplogroup that you get assigned to from your results.
I'd suggest that you both also consider whether you're comfortable with downloading and uploading your particular DNA results to a 3rd party site. If so, I'd suggest checking out the now-gearing-up mitoYDNA site (and read their terms/privacy policy).