Especially excluding fortune tellers?

Everyone's cognition of things is different.

You should remember that if one thing, especially between you two in-laws, doesn't affect or hurt your family, it's unnatural, even if it doesn't conform to your values, you shouldn't interfere too much.

Your wife thinks that it is at least a great comfort for her to deal with these things within her own ability, so she can devote herself to life more happily, so I suggest you observe. If she is deeply involved, you can persuade her. If not, you can have a look again.