they have. Carly went to her last week or something for info, and all looked good, the conversation was cival and happy, till carly realised she was lying, and bam, that probaby just reinforced to her, she cant trust her, or rely on her because she always lets you down. Dean the same. Shirley keeps making mistakes, you can tell she loves them, but she's let them down big time, of course they are going to be resentful of her. any child who's mother leaves when you are young and abandons you for 17 odd years while you grow up is going to be very angry and resentful. the strong unconditional bond children have with their parents, isnt there with carly because she hasnt brought her up or been in her life. she hasnt been a 'mother' to them in any sense of the word.
she needs to make small steps, and gain their trust gradually, because i do think they want a relationship with her underneath it all, deano deff.. and maybe they can have a cival relationship with her, but one suspects shirley will keep screwing up, she's just a character that you cant really trust because you always get let down in the end.