What is the ruling on the phrase: "So-and-so saved so-and-so from drowning," and is there any Sharia-based objection to it, and is it obligatory to say: "By the grace of Allah, then so-and-so saved him from drowning"?

There is no religious impediment to using the phrase "So-and-so rescued me" if the speaker believes that the true rescuer is Allah, and that the person was merely an instrument. However, it is preferable to say, "Allah rescued him through So-and-so" or "Allah rescued him, then So-and-so." It is permissible to say "So-and-so rescued me," believing that he was merely an instrument and that the entire matter belongs to Allah, based on the Prophet's (peace and blessings be upon him) statement regarding his uncle Abu Talib: "Were it not for me, he would have been in the lowest depths of Hellfire." It is not permissible to say, "Allah and So-and-so rescued me," because this associates an instrument with Allah using the conjunction "and" (waaw), which implies equality, as the Prophet (peace and blessings be upon him) said: "Have you made me an equal to Allah? Rather, [say] 'What Allah alone wills.'"