What should we do with islam here in America?
The same thing we do for all unbelievers: witness to them.
I do not view Islam as a "counterfeit," because it doesn't try to replicate Christianity. It is a cult, as every group that misidentifies Jesus Christ is. But we are called to love those who hate and persecute us, to preach to them the Gospel just as we should to any other cult. And like most cults, you're going to find people who "grew up in it." You'll find people who are associated because, well, the people are just so nice. People who were mistreated by "Christians." By Christian parents. By a society they couldn't relate to. But still people who need Christ.
God bless.