Should i ask them to pay back??

Okay guys i need help. Some weeks ago my husband let our friends ( a couple) borrow $150 since they were short on money. They havent paid him back or anything. My husband hasnt been working completely and all bills are this week and he’s short on money. He said he’s too shy to ask him to pay him back... She’s my bestfriend so i dont know if i should ask her ... and if i do how should i ask her in a polite way??