Manager asking me for money?

Ok so i recently got hooked up with a job through my uncle's best friend- ill call him JOE.. i have now been working here for 7 months now and things are going good. before i got this job i have never met joe before. so really i dont know his background, persona or things like that. i just know he is my uncle's best friend. In any case, JOE now has asked me TWICE to borrow money from me. first time he asked to borrow $1000. then today he called me and asked to borrow $500. telling me he needs to pay his bills, rent, kids school thing blah blah. i tell him dude, i have no money like that to let you or anyone borrow. He asks me to ask MY friends WTF?! really? i tell him i cant do that no one i know has that much money. what should i do if he does ask me again in the future? this is making me really uncomfortable. i feel although he got me the job or got my foot in the door, i dont owe him squat. but next time he approaches me asking me for money what should i tell him?? i haven't told my uncle i dont think i need to, my uncle did mention to me that his wife was about to divorce him cause of his "bad habits" JOE very much so loves fantasy football, spreadsheets and gambling? and he calls today after the superbowl. maybe he need to fulfill his Superbowl Debts? any advice would be great! thanks!