Wow.  I've never thought about this before, nor have noticed patterns in this category.  The best I can do is to recall my mother, who weighed about 250 lbs. and her home sewn "house dresses, which were pull overs (the dresses featured a yolk onto which the fabric  was gathered onto).   I would think that your friend would want something loose fitting, especially when surgical wounds are healing.  After that, she might be comfortable wearing pants with an elastisized waist, and a loose fitting top.  Things can be altered down within a thirty pound weight loss.  Anyway, these are just some thoughts.  Also, you might think of checking out resale shops...if you can find sizes to accomodate her it might be cheaper and certainly easier.  Good luck to you and your friend!

Kate