To wordswoman's comment I would add the opinion that the fact that Sage and Gabriel are your half-brothers is irrelevant to the beginning of the story. I would also add that the phrase "jumped at the chance" is inherently figurative, so the rest of the sentence is clearly just a vehicle to show that the protagonist is in a wheelchair. As such it is clunky, and that would make me tend to put the book down. If it is important (and I presume that it is) work it into the next few sentences.

To me the whole concept of a single "first line" that will hook the reader is flawed. Yes, the first line will determine whether I read the second. If it's bloody awful, the book closes. However, I will usually read at least the first paragraph, no matter what.