First, I'm sorry to hear of your circumstances. The first thing you should do is to document what repairs your home needs, and if you do have photos that would help.
I am assuming what you meant to say in your question is that your Assessed Value (for taxes) is 169,900. But that the new appraised value is $83,000. You will want to make a copy of your appraisal and the comparable homes that the appraiser used to determine your value.
Contact the West Allis Appraiser, and make an appointment to bring them your documentation.
They will then most likely make an appointment to come view your home, and start the review of your assessed value.
It's definitely worth a try. I had 6 Buyers last year successfully contest their assessments and get their taxes lowered.
Here's the link to the West Allis Assessor's Office:
All the Best to You!