advice wanted please:)

Hi All, Just looking for a bit of advice, My mother gave a baby boy up for adoption in 1979, she would have been roughly 27 when she got pregnant and as she was still living at home her father told her if she didnt give it up for adoption then she could move out, her aunty offered to take her in and help her look after the baby but as her aunty had enough children herself and was living in a tiny house that wasnt an option,my mother had no money and what life could she give him if they were out on the streets so she decided to give him to people who could give him what she couldnt she then went on to marry my father in 1981 and i came along in 1982. From a young age both myself and sister always knew we had a half brother out there it was ever hidden away from us, Roughly 8 years ago with some gentle encouragement from me she decided to make the move and look for him (part of her had always been afraid of what if he's no longer around doesnt want anything to do with her ect) we found out the agency that had placed him with his family and gave a social worker all the details that my mother had of him,some time after we recieved word from her that he had been found and that he was alive and well and living in Dublin.We were thrilled even more so when he was contacted about whether or not he would be open to contact from us he said yes! so to cut a long story short we exchanged letters at first and pictures and it was lovely, We both started emailing each other ,he said he had always wanted a sister and stuff like that ,he would end his emails with ' from your big brother' .It seemed like i was finally getting too know the brother whom i always knew about but had never had in my life, He was taking phone calls from my mother asking about his father and asking questions about my father getting as much info as possible ,he even put his fiance on the phone to speak to her a few times. Suddenly one day it starts getting sour he starts telling her he'll never want to meet her ect he starts backing away from the situation she rings him and he's totally distant with her she gets the impression he no longer wants contact with her so she tells him that she will stop ringing ect to give him time to think about stuff and that if he ever wants to contact her again that she will always 'leave the door open' for him, she is devasted but understands ,so fast forward 8 years she gets a phone call from the social worker in march telling her that he has contacted her and was adament to find out how my mother is ect she proceeded to tell her
that he has gotten married and is expecting a child in Sep, My mother is thrilled and tells her that she is fine ect and to pass her congratulations on to both him and his wife on the pregnancy she also tells her what she told him 8 years previously that the door is still open for him if he ever wants to contact her she gives the social worker an email address in case phone calls are a bit too much for him which he is apparently delighted with so 6 months later and theres still nothing....i would understand if this first time contact as i could only imagine what it would be like but this second time contact (if you can put it like that)

I am personally a bit upset as i had this contact with him and then it was just gone..Is it because of my mother that he stopped all contact with me? Part of me thinks this is all down to how little of an age gap there is between us 3 years is nothing..How she could give him away and then get married so soon after and have another child...how at 27 years of age she wasnt in a better position to hold on to him ,maybe now he has his own child he looks at him or her and gets hurt and upset at how she could have just gave him away...she had asked him was he angry and he said no that he understood does he think that my father is his father and that they just didnt want him? I have asked my mother this and she assures me thats this isnt the case. i think part of me is angry and upset that my children have an uncle and now a cousin (s) that they will ever know...Any advice will be most welcome as i dont know what to do.