Reading Francis Chan's "Forgotten God" - in the first chapter he writes that "another" denotes not a "different" counselor, but rather another of the same kind (p.34).
And I will ask the Father, and he will give you another Counselor to be with you forever— the Spirit of truth. The world cannot accept him, because it neither sees him nor knows him. But you know him, for he lives with you and will be in you. (John 14:16-17)
ἄλλος (allos) is simply "another;other) and is used 160 times. I'm not sure that Chan is quite right...but when Jesus was born, His parents returned to their home country in an "allos" route. Another (different) route.
From John 16:
But I tell you the truth: It is for your good that I am going away. Unless I go away, the Counselor will not come to you; but if I go, I will send him to you.
But when he, the Spirit of truth, comes, he will guide you into all truth. He will not speak on his own; he will speak only what he hears, and he will tell you what is yet to come. He will bring glory to me by taking from what is mine and making it known to you. All that belongs to the Father is mine. That is why I said the Spirit will take from what is mine and make it known to you.
I'm not sure that one can always take something said specifically to the apostles, and apply it universally, but the point that Chan makes remains:
Jesus had to leave so that the Spirit could come.
Chan says that having the Spirit with us - within us - is better than having Jesus Christ standing next to us.
The Spirit will remind us of what Jesus told His followers.
To them, the Spirit reminded them of the time they spent with Christ; as they penned the New Testament, they wrote as ones who had the Spirit within them, reminding them of what Jesus said and did.
To us...those Scriptures come to mind as we have need of them.
...as the storms of life loom on the horizon - maybe the storm will miss me this time, maybe it will sweep over me head on. Or maybe the last few months have simply been the peaceful eye of the storm.
Either way, Jesus said,
"You of little faith, why are you so afraid?"