Is it meant by "A Muslim's supplication for his brother Muslim in the unseen is answered" that the supplication is with or without being requested?

It appears that the hadith: "There is no Muslim servant who supplicates for his brother in his absence except that the angel says: 'And for you the like of it'," includes anyone who supplicates for his brother in his absence, whether he was asked to or not, because the phrase "ma min" [ما من] denotes generality.