He read his father’s voice echoing in his ear. Hearing the voice, he sat up in his bed and held his breath. It means the unexpected resonance from the voice made him restless, simultaneously, sad. "undressing" - interpreted both as being a reference on the sexual facet of their relationship, https://poemvalentinedaylove67899.pointblog.net/the-best-side-of-valentine-poem-for-husband-from-wife-75171072