AIO being angry at my brother prioritizing gifts over debt?

I (26F) lent my brother (19M) $2000 last year when he was in a really tight spot with student loan payments. He promised to pay me back within 6 months, but hasn't given me a dime yet.

Yesterday he told the family he won $50k betting on Stake. Instead of paying me back, he's buying everyone extravagant Christmas gifts - a new laptop for mom, PS5 for dad, designer purse for our sister.

When I pulled him aside and reminded him about the loan, he said "Christmas gifts are more important right now" and that he'll "pay me back eventually." I got angry and told him he's being irresponsible and disrespectful. He called me a Grinch for "trying to ruin everyone's Christmas."

Our parents think I should be happy he's being generous with his winnings. But I feel like he's using expensive gifts to buy everyone's approval while ignoring his actual responsibilities. The money he owes me was meant to help pay for my wedding next year.

I've stopped talking to him and told our parents I won't be attending Christmas if he's going to act like this. They say I'm being dramatic and need to let it go. But I feel like I'm taking crazy pills - am I overreacting here?

TLDR: Brother won $50k, is buying everyone expensive gifts instead of paying back the $2k he owes me. Now I'm the bad guy for being upset about it.