What does it mean when he says "You mean a lot to me" ?

I am not the type of person to get hung up on semantics... however... my boyfriend is very guarded and very deliberate when he opens up emotionally. We have been good friends for 12 years... and until about a year ago we were unable to pursue anything due to circumstance (he lived on the other side of the country).

Over the course of the last month ... He has really tried to be emotionally vulnerable and has

1) whispered ever-so quietly "i love you" in my ear post-coital afterglow (it was almost inaudible)

2) Recently signed a text "Love, [name]"

3) Introduced me to his friends and family - who openly articulated the "change" they see in him in terms of his affection for me

4) and wrote me a rather heartfelt email stating he is a "better man" since we came together (we have been dating for 10 months - all exclusively)... He then signed the same email "you mean a lot to me"

I guess I am wondering if he is "falling" in love? Does "you mean a lot to me" mean that in this context?

I should also caveat my question by saying he is in his late 30s (he is 10 years older than I) and has mentioned that he is looking for "someone to come home to" ... and is selling his sports car in the Fall because "it is time" and he isn't in that place in his life anymore. He already owns a home - and over the course of the last 6 months has completely decorated it professionally - in which he has sought my input.

Any thoughts? "What does you mean a lot to me" actually mean?

A close MALE friend of mine thinks he is going to propose within the next 6 months... what do you think?

I have no expectations whatsoever ... nor do I think a proposal is coming ... but I am interested from a guy's point of view as to where you think his mind is.