Do you mean 15 times after the resection, Twiglett, or while she has the colostomy? My friend's dd had a stoma then a pouch op for colitis. Once she had the op she did have to go to the loo quite a lot but it does settle down. In her case, it was because the large bowel had been removed altogether. The LB removes excess liquid from the 'gloop' in the gut but she'd lost that ability so everything was coming through runny (hope you're not eating while reading this!).
Taking Immodium on a regular basis helped enormously to regulate the gut, both in terms of looseness and in number of times she had to go to the loo. Certainly a pouch op isn't a quick fix, the body has to get used to its new way of working but as a teenager she felt it was a heck of a lot better than a bag. Other people may feel differently, of course. Has your friend been in touch with the Colitis/Crohns support group NACC (assuming that's what she has)? They are very good. Also the Colostomy Assoc . Not sure if this is of any help but I hope your friend is okay.