You love a person and you are not pretty much sure that he loves you too as u already told that he nvr expressed it. Now how do you knw that he loves you too?? Sometimes he use to get worried alot, but sometimes he dont care, look this is not a sign that he really loves you!! Maybe he only want you as a good friend. When you txt him, he use to rply late. May be he is busy at that time, this is not the sign that he loves you. Caring, Worrying doesnt means this is love!! And you are saying that he wants to get married with you, Who told you this? cz u guys nvr expressed your love. You both are relatives so in my opinion it is not good. Your parents nvr allow you guys to do this. And with all this ,it is not clear that it's love. So better think again and you guys can be good friends for life!!
stay blessed! hope this will help you!!