My husband died after a 7 month illness and my dad died two weeks to the day after that. My husband and I had been caring for my mom and dad for several years. I still care for my mom. My brother reluctantly came down to FL from NY for my husband's service; his wife did not. Neither one of them came back for my dad. I was left alone (Mom has dementia) to make all arrangements for my dad while going through (and still going through) the most heartbreaking time of my life. I expressed this to my brother just recently (about 6 weeks later), calmly and in the form of an email - his preferred method of communication. His response "Sorry that you feel that way." Should I even bother to mend this fence?
I think brother has shown you his boundary - he was attached to mom but not to dad. He's given you a very healthy response to your email, that he is sorry you feel that way. He may have been in therapy to get to that place. There may be issues with dad and or your husband that you don't know about. If brother wants to get in touch with you, he knows your email address. In the mean time, I would talk to a therapist about what went on and what to do now.