am I doing right to tell him like what firebug, ST3 etc is?
Honestly, if your company only values you because you know what those are then you aren't very valuable. It's how you use the technologies that makes you matter, not what technologies you know about - this isn't something someone you teach can replicate, and if they do it exactly like you after not doing it like you well then there is your clear indication to your management that it came from you. Even with all of that experience in something is still more valuable and clear and easy to see - this is also something that cannot be faked, and since you are using the technologies still and since before he knew about them you will always be better at them.
Someone told me he can leave you behind and might get in good graces, because he is vocal and he'll use my knowledge to impress the boss.
I don't know who told you that but it sounds like that person thinks it's them against the world instead of with the world. He's part of the 'team', you should be helping each other out.
Just teaching someone something or telling them about something isn't going to make them 'better and more valuable' then you simply because they vocalize it to management. Any novice talking about anything they are a novice in is very easy to see. Honestly most management would be pushed away from this person if they talked a big game on things they just learned, and like I said, it's easy to tell if someone just learned something.
There is a lot of value in just teaching, it's a win win, this toxic 'me before he/she' attitude is what will cause you issues.