Husband wanting to join military... advice


My husband and I have been married for 5 years and have 5 kids. He’s wanting to join but he’s scared they won’t except him. Anyone know what reasons they won’t accept you? He’s 26, has kids, has some tattoos nothing obvious just arms and chest. He’s working so hard right now training his body, making sure he can pass the requirements but he feels like they’ll reject him and he just wasted his time.

Also can any military or military spouses have any positive advice for him or for me? What branch are you and/or your spouse in? Pros & Cons?