The 'last' command gives all login history of all users.
last <username> | head -n1 will give you the last time that a user logged into the system.
One caveat - if the user has not logged in within the last year and the wtmp file has not been reset in that time, you may get a false positive. The last command does not report the year and you might show the user having logged in recently, but it's actually from over a year ago.
Geoff