My bro also plays as Lucario. My advice is to stay out of the air near him, his air game is exceptional. Superior to Pikachu's, so I have learned to deal with it.
If he starts spamming aura sphere, I like to just jump over them and just wait until he stops. Then HE has to approach YOU, which is good in your favor. Also if you have a projectile yourself, spam him back unless the aura sphere cancels it out, then just wait for him.
If you are on the ground and in a ground conflict, passing eachother attacks to trying to hit eachother, try short hopping to dodge him, get just above him and he will whiff most attacks, and you get a free aerial such as Toon Link's spike or MK's Dair or Fair. Or even a shuddle loop! Just don't full hop it, because he will come up and you will have an air fight-not good for you.
Also, check the Lucario boards for his good and bad matchups if you want a counter to him. Hope that helped!
Good luck man. =D