I, too, have no knowledge of Disney or Disney points. But I assume from your "she made a reservation for" that she proposes to rent a very specific timeshare at a very specific time.
As such, it's a standard "how do I rent?" question.
First and foremost, CAN you rent that week (as in, are you allowed to rent that week according to Disney rules)? I assume so, but that's the first thing I'd check. For example, if she had banked her week and traded it for another timeshare week via an exchange service like RCI, she would not be allowed to rent out her "traded into" week. RCI claims that, if they found out, they would cancel your account (no matter how much trading value you might have in the account). Cancel your reservation. Make your guests cry their eyes out in the resort lobby after finding out that their reservation just went Poof! and is no more (after the parents and three kids just arrived from the UK).
Assuming you would determine there are no restrictions on renting out your Disney-system-reserved week, my next question might be if the resort might provide a rental service. Oftentimes they do. They usually take 30 to 35% of the net proceeds, but that may work for your friend. They tell you upfront that there are no guarantees that they will be able to rent out an entire week or, indeed, any portion of the week. But if the resort/time of year is super high demand, that's perhaps not a bad choice.
If you want to control your own destiny and not leave it up to others, then my next question would be, "Can I rent for just a partial week, do a mid-week cleaning (for which I would pay), and then re-rent to another for the remaining days"? Some resorts will and some resorts won't.
If you are allowed to rent for a partial week, I would then place ads accordingly. People oftentimes don't want to rent for eight days and seven nights. During yesteryear, when families might have had five, six, seven kids (the Wholeys in my neighborhood had sixteen kids), a vacation meant non-stop entertainment for the kids who just wanted to go to the beach or the lake every day. Nowadays, adults are more inclined to lean towards "been there, done that" and might want to move on from Marco Island to Key West (as one example).
So where might you place these ads? TUG, Koala, redweek (upfront fee), myresortnetwork (upfront fee), airbnb (be careful with setting your one week's dates into your "calendar"), and a bunch of other possibilites. Some are good options for those seeking to rent out a week, some not so good.
Recognize also that, this year, resort areas that usually had many Canadian visitors (like Orlando or perhaps anywhere in Florida) will likely see a dropoff in Canadian tourism due to their American boycott.
