There might be a few reasons you want your older dog to learn to sleep in a kennel after all these years of not sleeping in a kennel. Kennels are small areas you can think of like your dog’s personal bedroom. If you are rescuing an older dog, a kennel will provide a safe place for him to rest and sleep, especially while you are away. A rescue dog cannot tell you his history. Though some owners feel it’s punishment to put their older dog in a kennel, if he has been rescued this confined space gives him the sense of safety and security especially while he's adjusting to his new home. If you are training your older dog to sleep in a kennel it might be because he has just gotten older and needs a place to feel safe and secure while also protecting your house, anxiety he might be facing in old age, or house training accidents he might be having as he gets older. Either way, he will need to get used to this change.
Your older dogs has a lifetime of habits built, so be patient while trying to train him to sleep in a kennel. If he is older and not always remembering where he is, you may need to take him to his kennel repeatedly before this becomes a routine for him. This repetitive training is important for breaking habits as well. While training your older dog to sleep in a kennel, it will be important to teach him that he is safe and secure and to always return with lots of love, attention, and of course the tasty treat for rewarding him for not only changing his old habits but also handling the change well. Be prepared for whining as your older dog may a protest change. If you can, try to be around as often as possible before leaving your older dog for long periods of time in this new space. This might mean you start training at night before leaving him all day long alone while you are away.
Start your training off prepared with a kennel set in a place where your older dog will be safe and comfortable. This area might be your bedroom, especially if he's going to be in there when you are gone or sleeping. This area could be a living space where you want your dog to be while your family is active and in community space. Provide lots of comfortable bedding and if he still has a lovey or toy, include that or maybe a couple of new toys. Also, be sure to have lots of tasty treats on hand to reward him. Schedule time to train your older dog to sleep in the kennel when you are not exhausted or stressed.