whining

First, get him to a vet for an exam and bloodwork. This is a behavior change and so he needs to be OK physically. Hearing and eyes need to be checked.

Whining is typically a sign of stress. It is not an easy thing to "stop" other than not rewarding the dog for it. Only reward the dog for silence. If the dog is whining for dinner, no dinner is served until the dog is silent. If the dog is whining for attention then he is ignored until he is silent. That is your best route.

FIRST get to a vet and get a thorough exam.

I some tips on how to get your dog’s whining under control. Example : Ignore them, Resist yelling or Praise calm behavior.
The reason your dog’s whining is to get your attention. I mean, any dog owner’s going to feel bad and look toward their whining dog. However, giving your dog attention enforces that whining gets them what they want.
So, if your dog starts whining, get up and move away from them. This action will make your dog understand that whining doesn’t gain them your attention. In fact, it does the opposite. At first, you leaving will only make the whining get louder. but if you want this behavior stopped, you need to power through. After a while, your dog will learn that whining doesn’t work and resort to other attention-getting tactics.

2-year-old thread.