and running a casino without enough funds for the bankroll it's almost impossible.
Yeah, for this reason alone I would recommend that everyone stays away from funding the loan. On his site, the max profit for crash is $1000:
The house edge for crash isn't listed, but the edge for other games is 2-5%. If we assume that crash has a 5% edge, then the kelly criterion suggests that they should have a bankroll of ~$20000 to be sustainable in the long run. Even if they choose to be more aggressive and take more risks, they should have a bankroll of at least $5000.
If he doesn't have this bankroll, then anyone betting on their site should be very concerned at him not being able to payout if people were to win. If he does have the bankroll, then he should just reduce the bankroll instead of trying to borrow 0.05
BTC (~$1000), and reduce the max win accordingly.
A likely outcome from this loan might be an exit scam both for the loan and his casino, which would render your domain "collateral" worthless.