What is the legal share of the heirs from a joint bank account between spouses, given that the wife was not employed and the husband was the one who deposited the money into this account?

If it is merely your permission for the wife to withdraw her needs from the money, then the children have no right to claim anything, as this permission does not imply ownership of the money for her. Rather, it must be proven that you have gifted her a part of it or that she is a partner in it.