How sound is the Hadith: "Whoever excessively invokes blessings upon me will not experience evil or harm at the time of death"?

It has not been proven that ease of extraction during the throes of death is among the virtues of sending blessings upon the Prophet (peace be upon him), as clarified by Al-Hafiz Al-Sakhawi in "Al-Qawl Al-Badi'." Nevertheless, sending blessings upon the Prophet (peace be upon him) is among the most blessed and beneficial deeds in matters of religion and worldly life.