Is there a way to to change the task appearance in the Project Update feed to include a parent tasks in addition to actual task that was commented on?

Can't be done directly on the Update Stream (I believe), but you can create an alternate view of the Update Stream using an embedded dashboard in your Project view, which would contain a Notes report. The notes report can show the parent task.

• Create a Notes Report. (filter is "Note Text is not blank - no other filters needed)
• Add this column of text mode to your notes report:

displayname=Parent

linkedname=task

namekey=view.relatedcolumn

namekeyargkey.0=task

namekeyargkey.1=parent:name

querysort=task:parent:name

textmode=true

valuefield=task:parent:name

valueformat=HTML

• Add the Notes Report to a new Dashboard, "Notes"
• Update the Layout Template options (or, achieve this manually on a per user basis by selecting the "Customize Tabs" option under "More" when viewing any project). You want to add your new Notes dashboard for users in the "Viewing a Project" tab options.
• Now, anytime you view any project, you will have a new tab called "Notes." It will display your notes report, and it will only show updates that were entered on the project that is being viewed.
• In addition to displaying your Parent Task column, you will want to invest some time in adding other columns and making it a nice report. The Updates Stream offers a lot of detail, so this approach to just get the parent task isn't great - you'll want to add more detail to your report. Attached is a screen capture of what we have done using this approach (with a lot of text mode applied). In fact, I will probably update our view. The one shown is a universal Notes view available in our system, but I think I will tailor this particular report to exclude Project and User, and add in Parent Task.

Good luck!