S.P.
I think it's helpful that you mentioned you came from another country.
It's true that words mean different things in different places.
If crud doesn't bother you or DH, then it's fine, imo.
If it does bother you, then it's not so fine.
You might want to come up w/a few alternative "bad" words
for DS to use when he's out among other people . . . .
just in case.
For example . . . . CHARD! or RUTABAGA!
A person can use just about any word as an expletive,
to blow off steam, but his choice of words can be meaningless
to the people around him.