HELP!! how do i respond to this??

[Silver]

But how can i argue with his logic when he says that our discussion has no meaning if God dosent exist because God is eternal life and truth..the one thing that we need to achive??

That's his illogical hang-up, not yours. Life exists as it does with absolutely no evidence of a god's presence; thus, one can logically posit that god does not exist and that the mere concept of god does not hold a monopoly on life, how it is perceived, or how it is lived to its fullest.