More than half of American households have pets. Companion animals are often considered part of the family.
An elderly person may find special comfort in the company of a pet after losing a spouse or friends. The attachment may be very strong.
Not much research has been done about grief over losing a pet. The available evidence says that this grief is like any grief. It resembles the grieving of a close friend or family member.
The grieving period varies. It can go on for weeks or several months. In one study, a third of those enrolled experienced grief for at least six months after a pet died.
You should seek help when grieving interferes with the ability to function. (This applies whether the person is mourning the loss of a person or an animal.) In the study I just cited, only a small percentage of people could no longer function because of losing their pet.
Is your uncle still getting out of bed in the morning? Is he eating regularly and otherwise functioning? Then he may just need more time and understanding. He will probably navigate the grief process fine.
Is the grief overwhelming his ability to care for himself? Then it may be time for him to see a mental health clinician. Your uncle may welcome advice about how to heal.