Is buying a sheep for Eid obligatory?

Assalamu alaikum. I’m a Czech guy living in the US, married to a Sudanese sister. Lately, my wife told me to send $200 to her mom back home for an Eid sheep. I got confused-she once mentioned the average monthly salary there is about $150, and she has five married sisters still in Sudan. So why me? I’m not even Muslim. Her family never sends me anything for Christmas either. It’s been over three months of them asking for Eid gifts, and honestly, it felt off. I didn’t send the cash. My wife was upset but moved on. Her family, though, is furious. Her mom called and said I’ve doomed them all to hell. Can that really be true? Did they really bet their souls on money from a person they never met? Is this a normal thing? Just trying to understand.