My friend owns roughly $1M USD worth of Bitcoin. These coins are sitting on a (backed up and encrypted) hard drive in Brasil. He bought these coins legitimately, and has the paper trail to prove it. 

He recently moved to the US, and now wants to get his coins and liquidate them.

I've been doing research on this topic, and I am unsure what kinda of taxes he will have to pay on these coins.

I've seen articles talking about capital gains tax from buying / selling coin, but he is not trading them in the US.

My thoughts lead me to think that this would be similar to him bringing over a ton of gold or other assets, and selling them off here, which makes me think of paying a sales tax.

As Bitcoin is still a newer development in the tax world, I am struggling to find any documentation on steps for this, so any feedback / options would be great.