M.L.
As with Disney movies in general, you'll get violence, sadness, teasing, bad behavior, and scary parts, plus some elements that seemed all right when the movie came out in 1941 but are not considered acceptable now.
Of course, children like bad behavior and scary parts and all that. Look at 2012 movies! I remember crying as a kid when Dumbo's mama was put in chains for charging her son's bullies. But I cry at everything.
The ending is happy, and that seems to resolve all the issues for little ones.
Why not rent it first? If your grandchildren really like it and want to see it again, then you could buy it.