Life Insurance/Annuity, can a non beneficiary contest it?

My father inlaw passed away a couple of months ago. A month prior to passing away, his wife of 30 years (2nd marriage) left him and filed for Legal Separation. After being served w/papers he changed his Life Insurance Policy Beneficiary to my husband. He also changed his Will leaving "his share" of financial & property assets to my husband, his only child. A week or so before he passed, he filed for divorce. Since his passing, his wife has contested the Life Insurance Policy and we believe "cashed out" part of the Annuity. Questions? Since his wife is contesting the Life Insurance Policy, w/her name not being listed as beneficiary can my husband contest the Annuity, if, he is not listed as a beneficiary? We are not sure of this as we don't have a copy of his Annuity Plan. The request is in progress. He is now the Executor of his father's estate.