My husband is making plans with friends who are unaware that he can’t follow through. Should I tell them he has dementia?

Yes, but not in front of him. At some point, your friends will become aware that your husband has issues and they will understand. After he makes his plans, call, email or text the friends and explain. It will only take one time and in the future, they will understand and humor him. However, keeping in touch with friends is important for your hubby. If he makes plans for a cookout or a lunch out, you carry them through for him. But if it’s a trip to Vegas or something else not doable, a well placed, private explanation to your friends is ok.