TWITLET:
Upon reading further up in the thread, I see you've already pasted your exact parsing error. Nicely done! The only good thing about errors is that they sometimes tell us exactly where the problem is, and fortunately that may indeed be the case here.
My interpretation of the error: WordPress is saying "I don't understand one of the brackets in line 409 of the functions.php component of the default template."
Great! Now we know exactly where the problem is, so how do we find it and fix it? There are only, like, fiddy billion brackets in a single template component, so just looking for one bracket won't work.
The error was nice to tell us exactly which line the rogue bracket is on. It's on line #409. Hmmm. the lines aren't numbered in the WP admin panel, are they? Boy, that's gonna be a pain to find line #409.
Just for grins, I changed my template to default, clicked on "Functions" in the right margin of Theme Editor window, then copied and pasted all text of Functions.php into an Excel spreadsheet which counted the lines for me.
Though I have less than 409 lines/rows in my Functions.php, you might have more lines if you've edited this component. It might be quicker for you to start looking from the bottom, then upward, at the Functions.php when hunting the naughty bracket.
So, how will you know which bracket is bad? If it were me, I'd want an untouched original to compare my "bad" one to. I'd locate an original, unedited Functions.php and compare mine to the original, starting from the bottom, then going up/backwards.
If you don't have a backup of the original "default" template components, maybe there's one available here at wordpress.org you can download to use for comparing against your existing Functions.php component.
Once you know what it's supposed to look like, and if yours looks different, then you'll know what to do to fix it.
If you've never edited your Functions.php, and if do you find an untouched original Functions.php, it might be quicker to just upload only an original Functions.php to your host, in the correct directory, to overwrite the one that's misbehaving.
Keep in mind that if you've edited your Functions.php already and don't want to lose the changes, then do NOT upload an original without making a backup copy first, as this would overwrite your edits.
If your first response on reading this is "But I'm not using the WordPress default template!", then do post an update on what template you are using so we can further ponder the situation.