Responses
They didnt forget, he was throwing a tantrum in the early episodes that he didnt get a pet he wished for(we just werent shown his birthday because it wasnt really needed I guess?). Although the part about adopting the girl is true lol
Bro I will be sad and mad as well if on my birthday my parents didn't remember it an they adopted a random girl on that IN MY BIRTHDAY yeah no shit I will despite her