Understandng how predestination and destiny work within reality could be helpful. Thing is, predetermination interferes with free will. However, time is not linear. Imagine, if you will, that all of our reality existed on a dvd. Your moment that you are experiencing, your perception, is a specific point of data on the disc. That does not mean that the data for all the rest of time does not exist at the very same moment on either side of that point.
Now, here is where it gets interesting, and, while this may sound more like fiction than fact, I assure you that this is, in fact, reality. Reality is a construct that is being held together by all of us. Our souls, if you will, power reality. We create reality in order to have a meaningful experience. Our souls, however, existing both inside and outside reality, can perceive the data that is on either side of the exact moment that we are proverbially watching on the DVD. Therefore, one who is in tune with one's soul may become privy to what will happen in the future. In addition to this, all of us here, all of our souls, are part of a group consciousness. Because we are creating reality together, we all decide on certain directions for us, as a whole, to travel. Thus, we create certain points that are, essentially, predetermined. Most things, however, do not effect the larger direction. Therefore, if you wish to make a change within reality, it likely wont affect consensus, and it will be able to happen without interference from others. Therefore, much of our choice is allowed to us.
So, what of destiny, you say ? Well, the thing is, each and everything within our reality is subject to choice. Consensus on even the largest of events and direction can change. So, if everyone, or the vast majority, chooses a different path for life, that consensus changes, and the data on the disc changes. Even though the point of perception is localized, all the data, past, present, and future, can all change in an instant.
This happens all the time. However, we are not aware of it. This is because our physical memories, the physical data being stored on our physical brains, is comprised of the data that has been along the point of perception on the previous segment of the DVD, which has changed. So, even though things changed throughout reality, we are unaware of it.
But, since the soul is able to perceive the data and exists outside of the physical data, it is able to perceive the changes. This is why someone is more likely to be privy to the changes if they are in tune with their soul.
So, basically, we have free will on a small scale, a large scale, and we have predetermination on a small scale (individual happenings that lead up to the events determined by consensus) and a large scale (consensus). If we, for ourselves, choose to change something that does not align with consensus, it will either be negated or will create a course correction throughout reality. For example, the hero could kill himself, creating a disagreement with consensus, since he does ultimately have free will, and, even though that WAS his destiny, now reality will have to shift to bring about the same end effect. (I dont mean necessarily that massive changes would happen, but things would start changing, leading up to the same conclusion, unless consensus changed as well)
Thats pretty much how things work in real life, so hopefully it helps your thoughts on your character.
And to those that would instantly write this off as ridiculous, if you have ever had deja vu, you have experienced it on some level. And, good luck explaining the observer effect or quantum mechanics.