Singh,
The MCV is so low that it seems iron deficiency must be part of the problem. Alpha is harder to detect, so I am assuming some HbH inclusion bodies were observed to give a diagnosis of alpha trait.
As Narendra mentioned, if you are clear of alpha trait yourself, there is no possibility of a child having HbH disease or worse. I would suggest a DNA analysis of your wife. If it proves she is an alpha trait carrier, you also need to be tested to rule out being a carrier yourself. Alpha is not easily detected, so a DNA analysis is the only sure method.