He's a feminist. He calls himself a feminist and that's what he is.
Good for him. And because there's no Feminist Central Committee to rubber stamp applications, then anyone, female or male, can call herself a feminist if she wants to.
Why does this matter to you and/or your husband? Why do you want validation from other feminists? It ought to be enough, surely, that he stands up for women's rights etc. Why does he need a badge to prove it?
It's quite a prize for a man to be recognised by the toughest audience of all – mean, scary feminists. It marks him out as special. He cares about people less privileged than himself. But isn't it just basic humanity? Supporting women's rights ought to be the default position for men. It's really not much to ask.
How do men perceive women who engage in feminist activism? Spiky and difficult. Various kinds of denigration and ostracism. Targets for MRA sob hate and violence.
When men are prepared to validate the work done by female women's rights activists, then they can start to demand that we validate what they do.