Replacing windows in a 120 years property

[Tal Shachar]

Hey there,

Hope I can learn from all the experienced landlords here...

I just had my inspection completed, for an investment townhome I'm interested in Baltimore, MD.
The house is ~120 years old, and besides the expected wear and tear, it is in a good shape overall

However, most of the windows as "past their EOL" and also, when opened, they do not stay up.
The house inspector told me that this could be a liability issue, if something happens to a tenant/child, due to a window shuts down on them.

Two questions, if I may - 

1. 1. Does anyone know how much does it cost to replace these old house windows? I think their size is not "Standard"
2. 2. Should I really be concerned about this "liability" issue?

This is my first investment property, so I'm not sure what to do with this info...

Thanks a lot for any insight!