My daughter had a broken foot when she was about 4, and was in a cast for a while. What I did was this:
Put a plastic bag around her foot up to her knee, wrapped a hand-towel around the cast at the top, put the bag around the towel and folded the towel down aroudn the bag, then secured the whole thing with a rubber band.
Had a milk-crate type thing that we turned upside down and then put a towel on, and she sat on that with her foot up on the side of the bathtub. I might have laid a towel on top of her leg then too
Used a hand-held shower to do her shower. If you don't have one already, you can get one pretty inexpensively at home depot. They are handy for cleaning the tub and showering small kids as well, so you would probalby use it after she is out of the cast.
Why don't they make waterproof casts! All the advancement in medicine and we're still dealing with this!?
Good luck!
“When one door of happiness closes, another opens; but often we look so long at the closed
door that we do not see the one which has been opened for us.”
Helen Keller (1880–1968)