Ah, ok. I wasn't making a derogatory comment - I didn't understand, as 'erstwhile' is usually used to describe someone who once occupied a role but is not doing so at present (eg a president or chairperson), so the role is still there, but currently filled by someone else. I think you mean 'estranged' brother, but anyway, it doesn't matter.
We all see these things differently, but as the will included grandchildren, as opposed to excluding you (eg by giving your brother the lion's share all to himself), I wouldn't see that as a slap in the face at all - as I say, I know that my mother's will does likewise and it doesn't upset me. If she has money left to leave when the time comes I will be grateful for it, and not resent the fact that my sister's side of the family will get more than either my brothers' or my own.
You do come across as thinking that life has been unfair to you, which is not an attitude that will ever make you happy. If you think you were born with the right to own a home because your parents did, to have half of the money they earned and saved to leave to charity instead of to their descendants, to be entitled to stay in an office job because you once had one and to have been more of a success than your brother because you are so much more intelligent, you are doomed to feel bad, as life doesn't work like that. We all make choices, and whilst life is kinder to some than to others, in the end we have to make our own way, and are entitled to nothing.