Sue, I pray for them and you. Please do not jeporadize yourself any further, yes they need help but they are making poor choices and will take you down if you let them,learn to let go and learn to say no. It is one thing when someone is struggling to do "better" and get ahead in life and they need help furthering their education and getting to work, but if someone is addicted to behavior that destroys all they have to support it, then you are only helping that, you are not helping them. You are only helping them stay in their disease another day. Be preparred for your own plan B if they do not pay your loan, people with this dysfunction never care of the debts, they only live for the expectancy of the thrill of next win from the gambling or the next high from the drug.
Sue I send you abundant blessings, including strength and wisdom. Please love yourself enough to not continue to be their victim. There is no need to have three people fall down.