There is no evidence that Ghandi said:
The measure of a civilization is how it treats its weakest members.
or
The greatness of a nation can be judged by how it treats its weakest member.
Ralph Keyes, quotation sleuth and author of the book The Quote Verifier found all alleged sources not verifiable.
Fortunately, we have something more tangible, from former’s US vice-president speech:
The moral test of government is how that government treats those who are in the dawn of life, the children; those who are in the twilight of life, the elderly; those who are in the shadows of life, the sick, the needy and the handicapped.