He also said, "My heart just dropped". That's a curious thing to say.

I guess as in 'dropped a beat'. The news was so surprising his heart stopped momentarily.

It's the opposite, usually. "My heart dropped" is a sense of doom, foreboding, a realisation of oncoming cataclysm. Like 'as I saw the second plane come into view my heart dropped'.

Of course, people don't use language in a consistent way, and people will use terms thinking they mean e.g. their antonym.

It's probably a common initial reaction to learning of impending parenthood. Life will never be the same. Initially one might only see the looming challenge of the mountain to climb.

I was going to explain the way i saw it, but i erased it and decided it's probably best not to give my thoughts in case he or someone in his life came across the comments out of respect.