See your friends last login on Facebook for iPad, iPhone or iPod
Find out when your friends last logged into Facebook on iOS
Here's how you can see the last time your friends logged into Facebook on the iPhone, iPad or iPod.
1. Tap the chat icon in the top right corner.
2. A list of friends will appear.
3. You can see the time that they last logged in on the right side.
For more, see the original article at the link below.