Coming back to this thread because I see a lot of founders make this mistake. YES use a SAFE, but also make sure you actually understand what you're signing your family up for.
A SAFE at a $2M cap means if you raise at $10M, your uncle's $10K becomes worth $50K on paper. But it also means if you never raise again and the company just... exists... that SAFE might never convert. It's not like a loan where they get their money back.
Make sure your family understands this is equity, not debt. Many families expect to "get their money back" eventually.