Looking for suggestions for apartment living room set up please

Looks like there is plenty of room for a sofa and desk. Dining table can be small. Search bistro table or small space dining. Maybe something with a drop leaf so it cn be against the wall and expand for company.

Since your son doesn't like facing facing the wall while working at his desk can the desk be arranged to face the window in the living room. That might not be the most ideal setup but hopefully the view thru the window would be pleasant enough while working.

Use lightweight ottomans and poufs instead of a coffee table. Comfortable padded dining chairs act as extra seating.
These are concepts only...I did not measure the pieces.

There was supposed to be an upholstered bench under the bedroom window and a tall bookcase next to the TV.

The desk below could also be at an angle and a corner desk style angled desk at a 45 degree angle facing the tv.

How about a desk that converts to a table? If you placed it in front of the window, then son will get a view, a work space and a dining table.

https://design-milk.com/a-working-desk-for-two-a-dining-table-for-six/?epik=dj0yJnU9VGpiX1lmT2RmUmtqR21IeWw0SEYycl93YWVpTDBOQ3UmcD0wJm49b2I4eDZNQWpfSnE0eEJ2Vjc0ZE9iQSZ0PUFBQUFBR1pqY3hV

There are two ways to place a desk in a window

1. There is space between the desk and the window for a chair that has its back against the window, and facing into the room while seated at the desk. This is the 'command' position as a CEO would sit. A swivel chair for the view.
2. The desk is against the wall under the window, so when seated at the desk the view is out the window. One has one's back to the room as in a desk in private quarters.

Either one is fine, just personal preference. A corner desk facing the tv is a good choice to still see the view. Use a roller chair.