What is your definition of non-scriptable? Just about everything is scriptable to some degree, but for the sake of an example lets use, does not contain an AppleScript dictionary, e.g. AppName.sdef within its application bundle.
For example, the macOS included Stickies application does not contain the Stickies.sdef file, and when trying to add it to the Library in Script Editor is says, "Unable to add the item because it is not scriptable."
In a case such as this, then System Events is needed to talk to the application process, e.g.:
Example AppleScript code:
if running of application "Stickies" then
tell application "System Events"
tell application process "Stickies"
set frontmost to true
if exists window 2 then ¬
perform action "AXRaise" of window 2
end tell
end tell
end if
Notes:
I've included error handling in the example AppleScript code, which can be removed if you prefer.