Just be there to talk to him and listen to him! Don't give advise untill and unless he ask for it.
Hangout with him once in a while. Or have a long conversation on phone if hanging out isn't possible
he is not ready to listening he always says I'm the reason for his loss and always says like that what can l do for it
Give him sometime to get out of his grieving process. Also you don't have to talk about whatever happened with him and his friends. You just clear it up that you wanna spend sometime with him. He will eventually open up to you and will let it all out.
I'm not ready for telling it again becz it will hurt him alot but he is comming to me telling iwill not say anything and even he will not make me sleep ngt becz he always says I m the reason for every thing
Now this is a new story!! All of He's pointing finger towards you. What did you do? Or What really happened?
actually I don't know
just talk to him as much as possible and support him, dont let him feel lonely, stay connected make him laugh, take him out for date or just usual walk. Just don't let him down.