Mexican Proverb equivalent

Solution 1:

Proverbs 14:20 reads

The poor are shunned even by their neighbors, but the rich have many friends.

[New International Version]

But this is far more transparent, and one version even helpfully [!] puts 'friends' in scare quotes. I think I'll start using the translation of the Mexican proverb.

Solution 2:

In the American Blues tradition, the expression

Nobody knows you when you['re] down and out

has been a familiar refrain for almost a hundred years. On YouTube, you can hear Bessie Smith's 1929 version of the blues song of that name. The sense of the expression is, of course, that everyone is your friend—and is happy to help you spend your money—when you're rich, but no one wants to associate with you if they can't derive any material benefit from it.

Solution 3:

Consider, A friend in need is a friend indeed

Almost always it is the origin of a phrase or saying that requires the most research, the meaning being well understood. This phrase is interesting because there are various interpretations of its meaning.

There is some debate about the meaning of this expression. Firstly, is it 'a friend in need is a friend indeed' or 'a friend in need is a friend in deed'? Secondly, is it 'a friend (when you are) in need' or 'a friend (who is) in need'? If the former, then the phrase means: 'someone who helps you when you are in need is a true friend'. If the latter, it is 'someone who needs your help becomes especially friendly in order to obtain it'.

The Phrase Finder

Al nopal solo lo buscan cuando tiene tunas

lit. "They only look for the cactus when it has prickly pears"

Means, they only look for you when they need your help

Quora