Hello !
Please keep up the good work of reaching out sincerely to another person. This world will always need people like you to be around.
God, in all His just and loving kindness makes the calling and does the choosing. I believed that he is the final judge as to what in particular "level of spirituality" a person should attain in order for him/her to be eligible for salvation. And this "level of spirituality"as numerous instances in the bible is always dependent on the specific circumstances of the people. salvation is a process. Christ even appoints 1000 years for the complete cleansing of the human race from all stains of demonic rule!
Having that said, you said that he is really a good friend. Well, I believe he is on the right track of becoming a true Christian in deed rather than in words. Maybe he is not doing the things that you have been thought christian should do or say to be saved.
I suggest just provide even the subtlest strategy for him to be acquainted with the bible, It has power. And its power to change a person is beyond our comprehension and is more powerful than any preacher out there. Let the bible do the talking. Give him and God time to reach out to each other. Come to think of it, God loves him more than we do ,rest assured that God will give every man the chance to earn life. Remember if no one will preach, then God will even make the stone to cry out ! just to reach every man.