I really hate when I see stuff like this. It just shows the true nature of most humans. This dude literally begged this guy to come to the casinos with him, his friend turned out to be super lucky and always wins, but yet he loses. Its hard to not feel bad for the guy who always loses but he should be happy for his friend. That's like teaching your bud how to play baseball and him becoming a huge star and you're just stuck in the outfield and cant make any catches or help plays move along. Maybe its time to find a new game my friend. Gambling isn't for you. The universe is telling him something haha
Being jealous is a normal emotional feeling, even when it's misplaced feeling of injustice, there's nothing wrong to feel that. And it's not like the guy is publicly blaming the lucky one for anything. He just don't want to go and the one who is asking should definitely respect his boundaries. And it's not even like the guy HATES his friend, he just hates being the one who is losing, and who wouldn't? And who says he hasn't been happy for his friend? What would you think if this would happen every time, to the point you didn't even want to go.
And being treated as a lucky charm isn't nice. If he wants to proof that point, he should just charge for being his lucky charm, or turn the tables and refuse by saying that "nah, you are bringing misfortune to me". It's basically as dehumanizing. It just sounds worse when you reverse the situation.