By his (Peace Be Upon Him) humanity, kindness, wisdom, sympathy and God (Allah) support.
He (PBUH) did not guide whom he chose, God Almighty guided those to embrace Islam.
The Qur'an says:
["Let there be no compulsion in religion: Truth stands out clear from Error: whoever rejects Taghut (evil) and believes in Allah hath grasped the most trust worthy hand-hold, that never breaks. And Allah heareth and knoweth all things. " (Qur'an 2:256)]