I don't think you'll be able to add-to the Down Nodes view itself and thereby add anything. These are 'canned' resource views which are often unchangable. However, I can think of one option which I use a lot...
Instead of using that existing Down Nodes view, you can build your own. What you might try is to make a custom view from using Report Writer and publish it to your screen.
First build your Device Comments for those nodes into Custom Property Editor for NODE. And then build a report with Report Writer using the fields for Nodes and Current Status and include that new NODE Custom Property.
Once you save your report go into Manage Views and then edit resource Network Summary Home and add or include your new report in this view. The green plus-sign is for adding resources. You'll see listed REPORT WRITER and then see 'Report from Orion Report Writer'. This is where you'll select the new report name you saved earlier. Select it and make any title changes .etc and it will then be listed on the screen.
Then if any nodes are showing down it will display those plus your Device Comments.