My mom was very good at dressmaking, and I've done some. Raglan sleeves are a little difficult to handle because narrowing the armpit w/o unpicking means that the sleeves get narrower, KWIM? Else the sleeves have to be takin off and the body of the jacket narrowed.
If it's not possible to take in some fabric from the body it's hard to do anything because basically the armholes are where they are, and short of adding an extra piece of material they can't be raised.
This is just from what I've done, so a professional dressmaker might be able to help much more!