It is not the norm. But if there is an estrangement in the family, it would not be unusual for all communication to be done via a solicitor & not a family member. It may seem cold, but at least it prevents any nasty scenes between family members.
No, readings of the will don't happen anymore. That is just Hollywood. You are entitled to be informed in a timely manner if you are a beneficiary of the will, not to actually be there when the envelope is opened, and the contents of the will read.
No, you are not entitled to see the full estate prior to distribution, just the part of it that pertains to you. You could ask the executors what your mums estate comprised of, but they are not legally obliged to tell you.
"Demands of the executors" for family photos? Using phrases like that and you are bound to tick them off. If your mother left her house & its contents to your brother, then the old family photo albums are now his. End of story. You could politely request that you be given access to them for old times sake, but they are his property now. He has no obligation to do so. Not unless they are comprise the few sentimental items that she specifically wanted to go to you.
No clue about the investment certs, but at a guess I imagine that they should be in the name of a third party until your kids reach the age of 21. That way an unscrupulous parent can't sell them and keep the money for themselves. Am not accusing you of doing that, but there is probably a set procedure for this kind of thing that they are following.