some help for a friends Dog

was talking to a friend tonight, who said, they may have to PTS there dog of 11 years. It seems that over the last few months the dog wont go outside to do his business, when they try to get him to get they have drag him. He said the dog seems to have lost his mind, he no longer acts like he used to.
He now seems scared of everything....

the dog has gone after the other dog(5 years old) sevela times, drawing blood, and having to take the younger dog to the vet to fix the damange.

My friend is worried that the 11 year old dog may go after one his little kids now, since the older dog seems to go off for no reason now.

i have no idea what to tell him, here. but i thought maybe someone here would have a idea.

The dog needs a senior blood panel done///

Often just like with cats dog s can have issues as they age .... if nothing shows up in the blood work then maybe discuss the use of herbal or chemical calming agents

I agree with the blood panel. Also have the thyroid checked. A poorly working thyroid can cause some aggression issues.

Also, if the older dog knows it's health isn't as good as it used to be, it may be feeling threatened by the younger dog (even if the younger dog isn't overtly being threatening). Afraid of losing it's hold over the K9 household and beating up the younger and stronger dog to try and secure it's dominance.