na mumkin ko mumkin me badal deti hai
ai mere falsafio, zor-e-dua dekho to.
well there are some acceptions, where prayers cant help anybody. e.g. physically dead body ist dead.
but on the other hand u can change almostly everything by praying, especially soul could be changed.
i met a german muslim, who was a crack person before he accepted islam. he was a drug taker. now he is a scholar of islam and very namazi parhezi banda. heart ka to Allah ko pata hai,magar bazahir he is a good insan. but due to taking a lot of drugs in his "zamana-e-jahiliyyat", he cant rid of these drugs, otherwise he will die. so he had changed his soul, but the consequences of his dealings on his body, he cant. so he got a fatwa about his situation that he is allowed to take drugs as a medical instrument.
if somebody doesnt accept ur help, then pray that he might accept help of anybody, who is best for him.
Note about my own opinion
sd 
