So when someone borrow it from you and they said they needed for their family but in the end he use it for gambling. What are you gonna do? Did you even follow him in everywhere, because when they need money most of them find many ways to earn it included cheating their only bestfriends. Until they dont know where to borrow again then they will go to loan shard to borrow with a higher interest
If you don't know your friend have problems with gambling then how can you call him your best friend?
You don't know who are you lending money to? As I said before, lending money to addicted gamblers is not a remedy, it's a poison for them.