I can understand your reluctance to pursue repayment of the debt, especially when your family member's circumstances have changed. However, a debt is still a debt and as such, it should be repaid!
You have the option of negotiating reduced payments with your family member until such times as their circumstances improve, whenever that may be! If they refuse to consider that, it is clear that they have no intentions paying you back!
If that is the case, and if you have something in writing between the parties involved, stating that the loan has been made and the amount, then you have the option of pursuing your family member through the courts for repayment of the debt, plus interest and associated costs! If there is no written agreement however, it would be impossible to prove that the loan was ever made in the first place! I am sure this last resort is a route you wouldn't want to go down, as it is likely to permanently damage your relationship with your family member!
You sound a very kind and generous person! I grew up as an in a well-off household, had to work hard for every single penny I got, and only received anything when my mother died and left me money and her house in her will! I was told from an early age by my father that borrowing or asking for money was a bad thing! As a result, I never asked for or got anything from him, apart from the basics, but I learned to fend for myself from an early age.
You say you would like the money back so you can help other family members. Given that you are having problems getting money back from one family member, is it really wise to even consider lending to another? Money really is the root of all evil, and especially where families are concerned. Sorry to sound so mercenary, but I myself have been through a very hard time financially, forced to claim disability benefits just to survive, then labeled a benefit scrounger by my daughter and her partner for doing so! I worked in a Senior Nursing position for over 30 years before having to retire early on health grounds, so I am hardly a scrounger! Needless to say, I now keep my distance from my daughter!