Corner of foundation broke off and tilted down

[Alex Housefinder]

So I am looking at buying an older house and we noticed the foundation on the back corner of the house has an issue. It's about a 4 foot section of the corner that seemed to have broke off and tilded down. They owners clearly did a patch in the pizza shaped opening that it caused on the side where it split off. It has pushed out a bit so the siding isn't completely verticle. It is pushed out. However, in the basement, the foundation looks fine except for a crack. So it seems the foundation split and the outer portion broke off and slid down. The house does show signs of some settling and movement but I am wondering if this is a serious structural issue or if it's more of a cosmetic thing. What would one even do to fix that? I'm feeling concerned about my purchase. Thanks!