What Modifies a Prepositional Phrase ?

[PaulMatthews]

Dear teachers,

I found the following sentence in a newspaper headline: Man molested daughter while she was asleep for 5 years.

1. Forgive me if I use the wrong linguistic terms, but am I right to say that the prepositional phrase (=for 5 years) is modified by the adverbial clause (=while she was asleep)

Man molested daughter while she was asleep for 5 years.

A point about the grammar: the PP (preposition phrase) "for five years" is not modified by "while she was asleep". The latter is a separate constituent functioning as an adjunct in clause structure, i.e. it modifies the verb "molest", just as the PP does.