An indie studio building not only its own engine but its own language to make its own engine seems like a huge mistake.
$4m alone (again, let alone his other games) would be enough to retire and make languges, engines and whatever else he wanted.
And with the Internet there isn't really a reason to limit yourself to people from US, a fraction of that would be enough to contract people from EU (though i'm certain you can also find people from US with much less than $500k/year-$1m/year to work on games).