Weight. The weight of the armour will stop him from making it. And since it would be unbreakable, it'll need so many condensed light that'll tire him out :D
Then his weapons would also be extremely heavy, as you said any of the constructs he touches becomes as strong as stickronium.
So if he can't carry the armor, how can he carry the weapons? Now onto other things about your character.
However, Murphy is not affected by this as his eyes are able to see in the dark.
This is different than what you said here;
He suffers the penalty when he is still human as well.
How about you go for some consistency, stop saying You'll change something one way, and then doing the EXACT OPPOSITE. You did the same with the teleportation.
But fine then, I'll remove the teleportation :D
You said you would get rid of the teleportation, but instead you kept the essence of it except under a different name, as seen below.
Murphy is capable of moving at the speed of light and resist the effects of friction, reduced oxygen, and kinetic impact while moving at that speed.
However, if Murphy holds one of the weapons- a light sword for instance- it will become as tough as Stickronium.
Proof that the weapon should be as heavy as the armor, so how do you make anything out of light if they are extremely heavy?
However, the exact thickness of the book is unknown due to its capability to add more pages itself, constantly giving Murphy new knowledge.
The book orbits around Murphy while shooting a small ray of light that passively heals him while providing light energy at the same time.
The book itself is completely overpowered, it gives you free power and healing, while you could literally super man your character at any time, "oh look a new page, learn this super devastating attack that can kill anything it touches!"
There's still the problem of if he was against someone who enjoyed breaking someone's willpower, Murphy would eventually heal himself and use the flare because, well, his will is broken. Your promises to do something mean nothing if you have no willpower to back it up.
I wish I could put in more than one "aye" on this character's overpoweredness, and I also wish I could put in an "aye" on you yourself. You are constantly trying to sneak around and try to secretly make your character overpowered without other people noticing.
We aren't stupid, we will notice.
EDIT: Also, stop spamming my visitor messages. I'm making sure to watch this thread. You don't need to send a message every post you make.