In the past, if someone whom I am not certain about came to me asking for Financial assistance, I would only give them the amount am comfortable losing in case they don't repay. For the case of family members or very close friends, I give them without expecting it back.
If I feel like I can't afford to lend out the money I have, i just simply tell them that I don't have anything I can lend out at that moment. If they offer any form of tangible collateral, then well and good.
This is the best method to adapt when borrowing money to family and friends, lend the amount of money that you can afford to loose, so in the case where they can not repay, it'll not affect the relationship. Money matters are very sensitive, so we need to apply wisdom while dealing on financial matters with loved ones, because it's easy for envy and enemity to set in. So best thing is not to let them to know your true financial position, so as to avoid unnecessary enemity when you can not support financially or lend a loved one.
One of the disadvantages of disclosing how much you're truly worth to family and friends is because some envious and wicked ones among them will keep coming back for more financial help or lending that they have no intention of repaying until they're sure that you're broke at come down to their label. Some can even connive with criminals to plot how to steal from you, or worse kidnap or even murder, it's an extreme assumption, but it happens.