<human>: Can you summarize the given text in a few sentences?

My dad has had a wine/champagne collection that he keeps in his basement ever since we moved into our current house about 5 years ago. He doesn't drink much, so the collection is more for show than for use at parties. I looked closer at it the other day and noticed he also had this gem: an opened bottle of Johnnie Walker black that was about 80% full. 

Since my dad doesn't do hard liquor, I know that it probably was there ever since we moved into the house, and it might have been opened before we moved in. Since I am older now and can enjoy the contents of this bottle, I would hate to see it wasted if the liquor was expired. Does a liquor bottle go bad if it's been opened and just kept there for 5+ years?
<bot>: Found an 80% full bottle of Johnnie black opened 5+ years ago. Has it gone bad or can I still drink it?