Customer just recently notified us verbally of an unauthorized charge on his statement that began last February, so notice is untimely. Bank is only required to investigate/dispute charges occurring within the first 60 days of the charge first posting to his statement, and he is then liable for the rest, since notice was not made timely. Is this correct?

Correct. Once the customer is out of the 60 day window, there is no responsibility on the bank.