I think you should see if you can get grief counseling (((Maddybaddy)))). Unfortunately, a lot of people don't know "how" to comfort someone experiencing grief. Giving the right support to someone who suffered a loss of a parent, especially when they witnessed their loved one die is something a person has to learn how to do. People who have not experienced a loss of a loved one don't understand the lonliness that comes with that loss, and it takes the survivor a while grieve a loss when they were so close with a parent.
I hear you regretting leaving where you were abroad to go home and care for your mother, and that you had to do that alone. But what you did for your mother WAS WONDERFUL, she was SO LUCKY to have a loving daughter be there for her until she passed. It sounds to me like you and your mother "loved" each other. Well, not everyone has that kind of relationship with their mother, in fact, a person can live their entire life not having the experience of that kind of love and closeness.
So, for you to get the kind of caring and comforting support you crave, you would have to find another individual who really understands the gravity of your loss. It does make a difference. Not everyone knows how to love that way ((Maddy)).
I am sorry your boyfriend has been on the cold side with you. I think what "he" is looking for is the person who loved and focused on "him" that you had been. See, you know HOW to love and appreciate, he may not. Some men are very uncomfortable with that, again no one really taught them. Before you commit, make sure you see how his father treats his mother, that is what he imprinted and "knows".