What should i do actualy my son(16 yrs)is sad .his 50 yrs old friend is away..?

he loves his teacher a 50 yrs old man whom he sits with at school and both speak about life and share there problems ,strangely enough the teacher responds to my son's conversation and problems ..but now at the summer vacation my son sees his teacher very rarely ..bec he has a family.. ...he doesn't call my son on his cell phone and my son thinks that he has been talking to him at school just not to hurt him but truely he doesn't care for him....what do u think does he realy care for him...and just his daily obligations is what keeps him away from my son....what do u think?..(actualy i'm the father and i tried to show my son love but it seems that he can't find in me what he's searching for..)