Dovid Does Kiruv

This story might take a few posts because it happened over many weeks.
A classmate of mine whom i am also a good friend of recently converted to Islam. when i met him in school he was an atheistic born Jew. Every once in a while he would ask me questions about Judaism, which i did my best to answer as best as I could not thinking too much about why he asked or why he cared. one of his questions was why is the Jewish religion so exclusive? another question that he asked was If the Jews believe that the Torah is the ultimate truth and is good for mankind why don't we do missionary work or at least encourage conversion? when i found out that he converted to Islam I actually had a nightmare that night. I do not remember the dream but i do remember waking up in great distress. That morning during shacharis I shed two tears while praying for him. I decided to call him and ask why he thinks Islam is the way to go and why Judaism is wrong. I know (and he told me) that he did research and he is very smart so i knew that he would be open to discuss the whole story. After he told me his side of the story I tried answering his questions and dilemmas but i obviously did not change his mind from one phone conversation, that by the way was more than an hour long. I took his questions to many of my Rebbeim and even some professionals in this field. They gave me excellent answers that i feel made me a better Yid.
The reason i asked so many people was not because they did not have good answers. They actually all said more or less the same thing. i just wanted to be prepared to trouble shoot if he twisted things on me.
why is the Jewish religion so exclusive?
If the Jews believe that the Torah is the ultimate truth and is good for mankind why don't we do missionary work or at least encourage conversion?
The answer to both questions kind of go together so i will just write in Divar Torah format.
First of all, till the time of the Romans the Jewish people did encourage conversion and did go around telling the world about G-d and the Torah. One example is Avraham Avinu and his four door tent that he tried to tell the world about G-d. another is when Moses left Egypt he took in the Airuv Rav whom are converts even though G-d himself warned that they will cause problems later on. the reason we stopped spreading the word of G-d during the Roman empire was because that was the time when schools started. this meant that many more people could now read and write and expose themselves to the Torah. the problem was that because ten percent of the roman population converted, the Romans sent double agents to convert just so they can stop the conversions and harm us.This led the Jews to change the way we spread the word of G-d to a passive approach. we act the way we should and this leads others to ask about our refined ways and opens conversation to people that are interested. we also have a system for conversion that keeps the non sincere people from converting. and if in the long run they sin and get punished for all their new rules that they are not keeping.
as for why we are a nation of chosen people i will give one answer now and build on it next time. our forefathers passed the tests that G-d gave them and therefore merited that their children will be the chosen people. it is not of our deeds but the deeds of our forefathers that we are born Jews. again, we are only the beginning of the system and all people are invited to see the word of G-d and convert but only if they are sincere. There is a Gimarah that states the reason for the exile (into so many lands) is so that the world will be exposed to the true Torah.