May we have as much background detail to this transfer to your brother’s name as possible please?
if your mother was simply transferring the property or part of the property or adding your brother to the deeds, he is not under any duty or obligation to contact every family member to advise them of what is happening unless he suspect this your mother did not have the mental capacity to enter into the transaction.
As this happened 11 years ago, then unless there is an element of fraud or some kind of coercion, whereby your mother didn’t understand what she was doing, I’m afraid the chances of you contesting this are going to be remote.
It doesn’t matter whether the solicitor has been struck off or not. It would depend on why the solicitor was struck off .
It may have been nothing to do with this.
If there was fraud, there is no time limit