The Prophet salla Allahu alaihi wa sallam had told us that Allah has appointed an angle to convey the salam of people saluting the Prophet.
He didn’t tell us that he also conveys people’s requests.
Not only that, the Prophet told us that on the Day of Judgment, innovators will be rejected from approaching the pool of the Prophet salla Allahu alaihi wa sallam. When he objects to that, he is told that “you don’t know what they had innovated after you”. he would then say: woe to those who change and innovate after me.
This means that he doesn’t know what is happening while he is in his grave.