It seems to me that you are being a friend to your friend of 27 years but that she is not reciprocating - I think you would make a fine friend - I do not think I would like your friend - from what you have written she seems to only want the "friendship" to be on her terms - as in do not ask her to step outside her own needs and ideas and beliefs. GEEEEZZZZ that is not real friendship. Do not beat yourself up over her behavior.

Your son still may just be too young to understand enough of the hardships in life to be able to understand and empathize with your life.

Short version - I think you can be a fine friend and I am sure that you are a marvelous Mom.