This script should return the date and time of a logged in OS X user's Active Directory password expiration. Please test and let me know if you get an accurate value.

get_ad_pass_expiration.sh

#!/bin/bash
USER=$(/usr/bin/python -c \
      'from SystemConfiguration import SCDynamicStoreCopyConsoleUser;\
       print SCDynamicStoreCopyConsoleUser(None, None, None)[0]')
xWin=$(/usr/bin/dscl localhost read /Search/Users/$USER \
       msDS-UserPasswordExpiryTimeComputed 2>/dev/null |\
       /usr/bin/awk '/dsAttrTypeNative/{print $NF}')
xUnix=$(echo "($xWin/10000000)-11644473600" | bc)
/bin/date -r $xUnix

• Is the output of the script accurate? Yes (well 28 seconds off of ADPassMon 2.10.1).
• What version of OS X are you running? 10.9.5
• What version if Windows is/are your DCs running? 2K8