Disclaimer: although I have experience building, I don't have personal experience with brick foundations.
How old is this house? If it is a newer house, that seems like a sign of shoddy masonry, though it doesn't look new in those photos, so probably not relevant.
Those cracks don't look that bad to me, and I have heard the rule of thumb of not worrying too much about cracks thinner than a pencil in old masonry, but idk
What I can comment on is that I doubt that level of shifting was caused by the drainage based on the info you have presented. It could be caused by the tree and that is something to assess
What? For those of us out of the loop please explain