Dear Renu,... Usually guys and girls in a new friendship of an intercaste kind tend to want to impress each other by experimenting each others cultures.
Believe me in college when North Indian guys liked a South Indian girl...they even go along to see Tamil movies..learn a few words of Tamil etc.
So its like a new phase for this OP's life..let her enjoy this moment..it might just remain friendship or they might develop a intellectual relationship even if they do not fall in love.
This is just a Chinna Chinna Asai in a person's life...so let's not make anyone feel alienated.
Some newly wed tambrahm girls add 'dA' while addressing their hubbies and hence don't want to get partners,
who are more than two years older to them. Some marry their classmates, who are a few months younger too!
May be, the OP can get a good friend, after meeting him in person, even if she does not marry him. :tea: