Welcome to planDisney Judy!
As it can be a bit confusing, I will try to help sort out the rules of
Theme Park Tickets at Walt Disney World.
Each guest will need to purchase a Theme Park Ticket.
Once used, they will expire and cannot be transferred or used at a later date. If your friends used 3 days of a 5 day ticket, those last 2 days will expire.
If a guest purchases a ticket and does not use the ticket at all, then the value of that ticket can be applied to a future date. However, once even one day is used, the clock starts ticking. The unused days are not able to be transferred to another guest either, so you cannot use their leftover days. If you want further clarification,
call a friendly Cast Member who can review your tickets for you.
I wish I had better news for you as I feel bad your travel pals were not able to use all their park days. However, I hope the time they did spend was magical and that you all had an enjoyable time together in Walt Disney World!
Cathy