After you find out more about his dad and Maggie goes to the cemetery --

How do I learn about Peter's father?

-- we need to see what we can do to make Peter go there too. Can you think of a reason that he might want to visit his father's grave?

Maybe if he thinks it's the anniversary of Dad's death, he might make a visit. (You can find his date of death on his headstone at the cemetery.) Go back to the gym and look for a way to change today's date.

There's a calendar right next to the door, and there's a dry erase marker right there. Use the marker to change the date to March 18. Now we just need to get Peter to look at the calendar.

Have Joey go into the men's locker room again and ask to reschedule his personal training session.

After Peter leaves, go to the cemetery to see the sad little three-sided conversation that ensues.

When that's done, Peter isn't exactly saved, but he is safe, at least temporarily.

How do I save all the ghosts?