o prophet you are not responsible for their guidance allah himself shows guidance to anyone he pleases. and whatever wealth you spend in charity it is for your own good. as you spend of your wealth to win allahs pleasure you will be given full reward for whatever you spend and you will not be deprived in the least of your rightful due.
ليس عليك هداهم ولكن الله يهدي من يشاء وما تنفقوا من خير فلأنفسكم وما تنفقون إلا ابتغاء وجه الله وما تنفقوا من خير يوف إليكم وأنتم لا تظلمون