I've just got a text from someone, who obviously knows me, because it said, 'Morning Maureen', but the number is not in my phone book. It then says, 'just want to let you know that mum passed away on Saturday....' 
How do I respond to that? Who ever it is, knows I've read it, because it's an iMessage. I need to say something, but how? I don't want to say, 'who are you obviously. It needs to be delicate. I am wracking my brains to think if anyone I know had a poorly mum or could it just have been sudden? I'm of an age when so many of my friends have parents over 75 tbh.