My wife was released from her position written as "non-casual dismissal" with no reason for her firing. They offered her 12 weeks pay again without any reason, is this fair?

Unfortunately, your employer can terminate you at any time, for any reason, as long as that reason is not discriminatory and as long as they provide you with the appropriate severance. I recommend reaching out to an employment lawyer at the number below in order to ensure that your wife does not have entitlements beyond the 12 weeks offered.