Hi,
Is your mom in acceptance of finding your brother?
If so, she can fill out the forms to apply for the open records of the child that was given up for adoption, and, provided a veto has not been filed by the other party, then the documents would disclose the adoptive name.
http://www.child.gov.ab.ca/whatwedo/...0Informa tion
If the link doesn't work, google
"Post adoption registry Alberta"
~Shannon