Can I get some perspective please? Divorce related

My parents are divorcing after 50 years.  At the beginning of May, my mom left my dad.  She left him a note and basically snuck out.  She told me she was leaving prior.  I totally get why she left but what I'm struggling with is that she is being so secretive.  She won't tell us where she's at.  I wanted to send her flowers for Mother's Day so I asked for her address.  She told me she didn't want to "disclose that information at this time".  She says she is scared of my dad but he is disabled and cannot drive because he's legally blind.  And it's not like we would tell him where she is at anyway.  

She has not talked to me or my brother since she left.  She says she is staying with a friend but then she told my mother in law she has a 6 month lease.  She has been talking to mother in law but even then she's very guarded on what she says.  I've just never seen this side of her.  She said she needed space. I've never been divorced so I have no idea what she's going through.  

She didn't even come to my dd's high school graduation or her dinner.  She knew my dad wasn't going to be there.  

They have been conversing through their lawyers dividing up property.  She has a cedar chest with mine and my brother's baby stuff.  She told my dad she didn't want it.  She used to be so sentimental so this has really thrown me for a loop.

Is it normal to cut your kids off too while going through a divorce?  My brother is furious with her but I'm really trying to be patient and extend her grace.  I'm just trying to understand.  Any advice would be greatly appreciated!