:salamext:
This is a comparative religion topic and that section is currently closed, hence this will also be closed.
We already have many threads and posts on the issues raised in your post, so try searching the Comparative Religion and Clarifications about Islam sections. This post has many relevant links:
http://www.islamicboard.com/clarific...ml#post1542744
In the end, you can only do so much. Be careful of spending too much time debating with and spending time in the company of such a person, as it is dangerous for your own eemaan. Focus on studying Islam rather than giving ear to attacks from others.