In Mudrarakshasa (an ancient play in Sanskrit), the character Arya Chanakya says, ‘I don’t mind if my own people and my relatives leave me; let all those who flocked round me for my wealth leave, let the army desert me, let me lose all my money, I don’t mind. I care only for my intellect; my intellect should never desert me. That is all I need.’
Not sure I agree with this, as I find this line of reasoning just way too strong. I mean, intellect or the proper functioning of brain is at the end of the day, a physiological feature of human body, which will deteriorate with age. It's your kin and near and dear ones, who will stay with you then.