Here are a few cockatoo plushies that I found on Amazon and elsewhere:
Mary Meyer Putty Stuffed Animal Soft Toy, Cream Cockatoo, 12 inches https://www.amazon.com/dp/B07YP6RQKK/ref=cm_sw_r_awdo_navT_g_HQEGCBRSW4FC8E9ME68K
Wild Republic Unlikely Friendships Plush Cockatoo and a Cat, Based on a True Story, Gift for Kids, Plush Toys https://www.amazon.com/dp/B0879Y4D14/ref=cm_sw_r_awdo_navT_g_N60JDK1804R45GM6N66T
If you are looking for something more individualized, I would recommend looking on Etsy. There are many talented artists that make knitted, crocheted, or felted animals/birds. Even if they do not offer Goffins Cockatoos, they might take requests.
For example, this artist creates really amazing realistic felt sculptures and portraits. The price is higher that a normal stuffed animal, but the quality is equally high. They offer a variety of birds, including cockatoos, and will make custom orders, based on a pet picture.
Speckled Fawn Felting
Shop Needle felted sculptures, cruelty free, ecofriendly by SpeckledFawnFelting located in Poznan, Poland. Speedy replies! Has a history of replying to messages quickly. Rave reviews! Average review rating is 4.8 or higher
www.etsy.com
If you want something truly unique to remember your bird, you might also want to look into pet portraits. Quite a few artists on Etsy and elsewhere will take a favorite photograph and turn it into a beautiful painting. I think it is a wonderful way to commemorate a beloved companion and it helps preserve your favorite digital photograph in a physical way. There are even some folks here on the avenue that might draw your bird for free!
Good luck!