I was going to say that you should consider whether your client should participate in the streamlined procedures to limit his/her exposure.  But seeing that your client already received a notice, I think your client may no longer be eligible since even a CP-2000, which is processed as an AUR, is still considered an examination.

Before you file the amended returns and FBAR's, you may like to take a deeper dive with your client why these accounts are being maintained (since domestic taxpayers with no overseas dealings don't tend to have these accounts), which could help unearth whether there are other offshore arrangements or transactions you may not be aware of, especially if the balances fluctuates quite a bit.  You may find that your client has (or had) other accounts such as pensions from previous employers, etc.

I'd tread carefully with this one.