I am deeply sorry for your loss of Thor
A few years ago,I lost Smokey,the TAG after nearly 30 years. Amy had know Smokes all her life. Amy came to kive with Smokey and I at just 4 months old and she was 26 years old when Smokey passed away.
Amy became VERY depressed,along with me. She wouldn't make a sound,wouldn't come out of her house,and just sat on her nite nite perch for WEEKS.
I have had two birds for nearly 30 years,and WE needed another one! I adopted Jonesy,a Goffin 'too from a friend...that brought Amy out of her depression in days, but I ended up rehoming Jonesy after a year or so (long story) They became fast friends.
So BB,a 4.5 month old cockatiel came home with me about 1.7 years ago..Amy wants to be best buds with BB,but BB is a little lerry of the "big green monster" but tolerates Amy.
I showed Amy extra attention,gave her more lovey time,took her out a lot to help her heal.
You might want to do the same with your CAG.
These creatures know,and feel,and understand love and pain and every other feeling/emotion. You'd be a fool to think not!
Maybe a new buddy is in order,but you NEVER know how the other birdie will react. I'm just lucky to where Amy LOVES everyone and everything
I wish you luck!
Jim