AJ, welcome to the board. Hope you get your slots in the Lottery. If it is a weekend, it's a long shot. But if you come mid-week, you are sure to get a slot from all the no-shows.
...just like your friend, many people drop out. Their slots become available to those who show up.
Now, if you really want to come out and climb Mt Whitney, just do it. You will meet a lot of others doing the same thing, so you won't be alone.
Be sure to check out the "Orientation Notes" (in the box to the left). They will help you understand anything and everything as you get ready to come and hike.