In adversity, we know our true friends

आतुरे व्यसने प्राप्ते
दुर्भिक्षे शत्रुसङ्कटे ।
राजद्वारे श्मशाने च
यस्तिष्ठति स बान्धवः ॥

- चाणक्यनीतिः

When you are suffering from a rare disease (or addiction), when in times of natural calamity, when you are afraid of your enemy, when you are at the doorstep of the king (to discuss your problems) or in a graveyard (when someone close to you dies), whoever stands by you is a true kinsman.

A friend in need is a friend indeed.
It is prosperity that gives us friends, adversity that proves them.
In prosperity, our friends know us.
In adversity, we know our friends.