How should we parent a grown child when there are also two younger children in the home? We have three kids altogether: a boy and a girl who are still in high school, and an older son in his mid‐20s. The oldest has had some tough luck recently and needs to move back home for a while. We realize that he’s an adult and that we’ll have to treat him differently in terms of rules and expectations, but we’re concerned about the effect this might have on his younger brother and sister. Do you have any advice?

If your oldest son plans to move back into the house, your relationship will have to be revamped in some fundamental ways. Though you and your spouse are still his mom and dad and care about him as intensely as ever, he is now an adult and needs to be respected and treated as such. You’re no longer in the business of “raising” him. That task is complete. The lines of connection between you have shifted from vertical to horizontal. Though in a certain sense he will always be your “child,” he is nevertheless your peer. So. while you should continue to nurture and validate him in any way you can, your basic role has changed from guide and director to advisor or mentor.

Does this mean that he’s no longer subject to rules of any kind? Certainly not. At least not while he’s living under your roof. But from this point forward you should expect nothing of him that you wouldn’t expect from any other adult boarder renting a room in your house. Rules are essential wherever people share living space. In this instance, however, they don’t exist to control or shape your son’s behavior. Among peers, rules function primarily to ensure safety and preserve order. In other words, the guidelines you implement shouldn’t be directed primarily at your son’s attitudes and actions. Their purpose is to safeguard the best interests of the entire household.

If you and your twenty‐something son are to coexist peacefully under the same roof, you’re going to have to identify what’s yours and what isn’t. You’ll also need to learn how to tell the difference between the things you can control and the things you can’t. Perhaps first and foremost, you must realize that you can’t dictate the behavior of another adult. It’s not up to you to say, “Son, I will not allow you to smoke or drink.” On the other hand, you can choose to make your home a tobacco‐ and alcohol‐free zone – maintaining the home as a safe place is imperative for the younger children (Asset #10: Safety). It’s your house, your mortgage payment, and your decision. This is not a question of telling your adult son “what to do” or “how to run his life.” It’s simply a matter of exercising ownership rights, eliminating chaos, and protecting the other members of the family.

In the same way, it’s entirely reasonable to insist that every member of the house pick up after himself or herself and keep family areas (living room, kitchen, bathroom) clear of personal clutter. Appropriate respect for other people’s privacy and property must also be maintained – for example, tools, clothing, vehicles, and money. Everyone should agree to uphold family standards of decency and propriety. If it is decided that the older son will help shoulder some of the financial burden of running the household, don’t be afraid to hold him to his promise. Also, a healthy reminder to him that there are “little‐eyes” watching and looking up to him. Encourage him to use his influence in a positive way and remind him that his younger siblings need other adult relationships (Asset #3).

The trick here is to avoid being blindsided by your emotions. It will be all too easy to slip back into old parent‐child patterns of behavior. If that happens, you may be tempted to let things slide that would never be tolerated in a normal adult‐to‐adult relationship. Be very careful to handle all of this precisely as you would manage any business agreement with any boarder or renter. Draw up a written contract if you think it might be helpful. If the boarder (your son) refuses to respect the rules or to follow through on his end of the bargain, let him know that he’s free to look for a new living situation. Remember, if he’s over eighteen years of age you are not obligated to pay his way or protect him from the world’s hard knocks.

Will this arrangement have a negative impact upon your two teenagers? We don’t see why it should. The key is to clarify the distinction between minors and adults. As part of that process, you can explain the reasons for the different sets of rules that will be in force while their older brother is living at home. This is a great opportunity to explain healthy family boundaries (Asset #11) and help your younger children to see how they change as responsibility increases with age. Meanwhile, you might also assure them that the time is rapidly approaching when they, too, will have to carry the entire burden of responsibility for their behavior. As teens, they should already be moving in that direction. No doubt you’ve discovered that an adolescent isn’t much easier to control than a young adult.