/diy/ - Do It Yourself

So a few years back, my father decided he wanted to buy a pool table.

After paying for it, and moving all the pieces in, he realized it would not fit "playably" in our basement; This lead to him moving the part up to the attic to use there, only to find that the room he had placed it in was also not large enough.

He then proceeded to tear down the paneling separating said room from an adjacent one. Unsure as to whether the wall was structural/supporting or not, he went no further.

Fast forward 5 or 6 years, and it's still in the same condition. I'd like to remedy this, but to do so, I need to know if it's safe to remove(non-supporting) or if I should just put a wall back up/only take out part of the wall.

tl;dr Don't know if wall is supporting or not, need advice.

Rough sketch of floor plan.