It completely depends on his financial situation and what kinds of accounts he has in the UK. If he has nothing but a modest bank account, that's one thing, but if he has any bank or securities accounts that trigger the FBAR or 8938, things get complicated quickly.
To be honest, he can probably do it himself with TurboTax as long as he is careful when it comes to both of the aforementioned forms. One other option: hire a professional to do it the first time, and then he can prob do it himself in subsequent years.