anyone else experience this??

i have a 7 year old boy and a 2 year old girl. usually he is the sweetest towards her and worries for her like she’s the most important thing in the world to him. however, he has adhd and he is constantly getting attention every day over his attitude towards me/not listening being defiant. he’s never shown any signs of being jealous. yesterday was my daughters second birthday party and when i tell you he threw a fit the WHOLE time, i mean it. he begged to open presents, i had to ask him to get out of the way and sit down because he was trying to rip into her presents and she was getting upset. he cried because my aunt was hugging my daughter, he cried and had a huge temper tantrum because someone gave her a $20 bill and he actually tried to rip it out of my hand and said it was his. today is the day after the party and he just got caught going through the bag the $20 was in, he said he was getting “his money”. im just at a loss, he isn’t typically like this and i don’t want to be the parent that has kids that have to blow candles out/open presents on the other one’s birthday. i feel like that just takes away so much from the other kid and i don’t want to make anyone feel left out. i also don’t want him to have a temper tantrum on every birthday she has, though.