The grief books assume you're mourning someone wonderful. But maybe the person who died also hurt you - was absent, or cruel, or drank, or left, or was simply impossible in ways that shaped your whole life. And now they're gone, and what you feel is a tangle nobody brings casseroles for: grief and relief and anger and a strange hollow where something was supposed to be.
Here is the permission the books skip: you're grieving more than a person. You're grieving the relationship you deserved and now can never have. The apology that will never come. The version of them that existed in glimpses, or only in your hope. That grief is real - sometimes it's the heaviest kind, because it's grief for something that never got to exist.
Relief is allowed. Not missing them much is allowed. Missing them desperately despite everything is also allowed, and so is all three in one afternoon. Complicated people leave complicated grief; the feelings match the facts.
And you don't owe the funeral version of them your silence or your endorsement. You can honor the truth quietly, on your own terms, and grieve exactly what was - no more, and no less. Nobody else got to live your side of it. Nobody else gets to grade it.