I'm the one working on information for pooh-sized people.
It's still coming! I've just been sidetracked because my wedding is in just a few weeks.
Once the wedding and honeymoon are done, I promise I'll get back on top of doing the information for pooh-sized folks!
As for your friend, a weight doesn't always help. Height, and measurements is usually the best way to help judge.
But generally, Walt Disney World is very accomodating for people of size. I'm 6'2", and when I went as pooh-sized, I was 352 pounds, with a 54 inch waist. I'm not entirely sure what my chest size was. There was nothing, (and I mean nothing) I had a problem with.
I didn't go on Astro Orbiter, or Dumbo, so I can't comment on those. I also didn't try the Tower of Terror until later, but it doesn't matter, because they changed the restraint systems anyway!

I also didn't try Splash Mountain, because it was out for rehab.
The only thing that I had a "problem" with was Space Mountain. It's not that I didn't fit, it just took some element of grace and decorum to get in without making myself look like a complete fool!
Your friend should be fine.