He is definitely Heather's child. You could pick him out of a nursery no problem.
Both beautiful human beings, by the way...
I have a recommendation. This is something I would have done had I known then what I know now.
1) Learn sign language ASAP.
2) Start communicating with your child via sign language as you speak to them. They understand speech before they're able to articulate phonemes. You'll find that they'll take first to the signing, and ultimately will convert to both sign language and verbal speech.
I've seen this in the works with one of our new karate students. Crystal has a very active and precocious 2-year-old. She communicates simultaneously via sign and verbal language now. Crystal is also teaching her both Spanish and whatever Japanese she learns from me.
Babies' brains are very plastic to language at an early age. The earlier you learn a language, the more likely your brain will treat it as a first language.
Boys in particular need all the head start they can get. We're great on the spatial, but a little slow on the language development.
One more thing... Here's a trick on how to teach them to do a sokusen when they grow up. You start at this age. It's very simple, and kind of sweet. Take your finger and have them try to "hold finger" with their toes. They will do it naturally. It's a reflex that has been in hominids for tens of thousands of years - probably back to the days when we could hold onto branches in trees with our feet, or on to mommy's fur when she had to swing from the trees. When doing this, you can adjust their grip so that they do it with a sokusen-like orientation.