As a teacher, I can attest to the fact that you can sow seeds. some of them will germinate n bloom whereas others will falter n perish. Such is the nature of life. Just remember that you are doing God’s work. Maybe the timing is not right for S now. But just like how some of my students blossomed years later after I taught them, maybe he will do so too. Just keep doing what you’re doing and leave the rest to God