Answer:
The impression of Roger that the author gives by describing him as a frail and willow-wild is the impression of someone weak.
Explanation:
After reading this description done by the author, the reader can infer that Roger is a weak person, not only in his wills but also in his appearance. By saying that someone is frail and willow-wild, we're describing someone whose body is fragile, someone that is probably not well eaten and dizzy. We, as readers, can imagine someone thin and maybe misaligned, weak in temper and health.
