Just took a glance at the story, and I think you're off to a great start! I appreciated the fact that you went out of your way to make the father somewhat sympathetic with an actual motivation, and showed that the main character cared about his brother. I think a lot of people would have just make them caricatures making life difficult for Our Hero out of pure spite.
But I did notice a few issues, that I'm only mentioning because you seemed to genuinely want some constructive criticism. (possibly some of this has already been brought up, just kind of skimmed the thread)
The first thing that popped out at me is that you need to get a better handle on how punctuation in dialogue works. (This seems to be an area everybody struggles with at first, at the writing workshop site I used to hang out at that was like 95% percent of the technical issues we would have to point out when going over a new members work...) But never fear, just use the following examples and I'll have you turned into a perfectionist grammar nazi yourself in no time flat! :)
"It Is mine to command, brother." You answer.
should be: "It Is mine to command, brother," you answer. (If the dialogue and the tag are both part of the sentence, always end the dialogue with a comma and don't capitalize the tag. Use lowercase even when ending a line of dialogue in a question mark or exclamation point, too.)
That one rule would fix most of the issues I spotted, the handful of others are pretty random and look more like simple typos to me.
Oh, and just fyi, if you flip it around, it becomes: You answer, "It IS mind to command, brother."
Also, if you have an action after a tag that's it's own sentence (rather than some variation of 'so-and-so says', that would be where you write it with 'normal' capitalization. "Blah blah blah." Mr. Magoo sighed and shook his head. "Blab blah blah blah blah blah..."
There, clear as mud, right?
Anyway, the second smaller thing I noticed is that you start sentences with 'You' a bit too often. Or it's more like, sentences AND paragraphs, because there are so many paragraphs that basically seem to consist of just one or two lines. It's an awful lot of white space and IMO interrupts the story's flow somewhat when reading.
Oh yeah, and I'm assuming you'll establish more clearly what the character is capable of in later segments and any limitations his powers might have? Right now we know he can control the weather and read minds, which at first glance aren't really all that related, and also have the potential (especially the mind reading one) to make it difficult when it comes to creating realistic challenges for him, careful not to write yourself into a corner there. (Don't want the readers complaining, 'Why didn't he realize Mr. Magoo was the bad guy and about to betray him, he could read his mind!' and so on.)
Though it does sound like the mysterious Venitor might be able to give him a run for his money either way, so I'm assuming you've got that part all under control. :)
