Where to use "only" in a sentence is a moot question, one of the mootest questions in all rhetoric. The purist will say that the expression: "He only died last week," is incorrect, and that it should be: "He died only last week." The purist's contention is that the first sentence, if carried out to a natural conclusion, would give us something like this: "He only died last week, he didn't do anything else, that's all he did." It isn't a natural conclusion, however, because nobody would say that and if anybody did it would be likely to lead to stomping of feet and clapping of hands, because it is one of the singy-songy expressions which set a certain type of person to acting rowdy and becoming unmanageable. It is better just to let the expression go, either one way or the other, because, after all, this particular sentence is of no importance except in cases where one is breaking the news to a mother. In such cases one should begin with: "Mrs Gormley, your son has had an accident," or: "Mrs. Gormley, your son is not so good," and then lead up gently to: "He died only last week."
Ladies' and Gentlemen's Guide to Modern English Usage