It depends. For cases where someone (family) is in a tight spot and just needs some help, but who is otherwise acting responsibly, it is either a gift or a "pay me whenever you can" deal if that makes everyone feel better. These are with money that can be lost if it goes that way and are mentally accounted for as gifts.
But I do think there is a place for more structured intra-family loans. Offering a mortgage or similar loan to a responsible family member, for less than market rates, but for similar to what might be available in 5 yr CDs, for example, can work out well. As a matter of extended family wealth preservation, it's far better for a smaller amount of interest to stay in the family than for a larger amount to go to a bank or mortgage company. The borrower can save significantly on annual cash outlay and the lender gets a modest income stream.It's simple to set up a basic loan agreement, payment table and auto-transfer of monthly payments. It's a reasonable way help out with larger amounts than one is willing or able to gift. The key is a clear understanding, automating transfers and a borrower with a dependable income.
In-laws helped us with low interest mortgages when we were starting out, saving us a bunch along the way, for which we are thankful. Now we are able to help a retired family member (who is living on a limited but stable income) in a similar way.