How would Bowlby analyze the effect of the death of a 20 month old
males mother? What questions would he want answered? What would he
expect the outcome to be?

There is a great book about attachment and also inherently about
Bowlby (the "father" of attachment research) by Virginia L. Colin
called "Human Attachment."  It was published by McGraw-Hill in 1996. 
There may be a newer edition out now, but I'm not sure about that. 
You would probably find it pretty helpful in answering your question.

You may also want to clarify why you are asking that question. 
Frankly, it sounds kind of like a homework assignment or test
question, which Google Answers researchers should not reply to.

Dear runner58,

I suspect your best resources may be the books by Bowlby: Loss Sadness
and Depression (Attachment and Loss) and Maternal Care and Mental
Health.

A couple of links that may be of use:

The Grief Process
http://med.usd.edu/som/genetics/curriculum/4DGRIEF4.htm

Family Grief and Recover Process when a Baby
Dieshttp://herkules.oulu.fi/isbn9514254295/isbn9514254295.pdf

Loss and Grief
http://www.hc-sc.gc.ca/hppb/childhood-youth/cyfh/pdf/fcmc/fcmc08.pdf

Support for a Family in Grief
http://acta.uta.fi/pdf/951-44-4765-4.pdf

Regards,