B737 Captain reported an unstable approach due to terrain and glide slope configuration warnings. Flight crew arrested excessive sink rate and landed.

Narrative

FO and CAPT (Captain) had flown together a few times; always on this route; but not recently. Returning to ZZZ from ZZZ1; FO elected to do visual approach by intercepting an arc and the ILS XL (XXX.X) less than 3 miles from the end of the runway. Level at 1500 feet crossing the shoreline; the CAPT queried as to whether FO wanted touchdown (300 ft) put in altitude window. FO replied in an oh yeah; that's what I'm trying to say" manner. CAPT called out "1000 ft" as FO lined up with runway (slight overshoot) and dialed in missed approach altitude (3000 ft) when FO didn't reply to callout. CAPT then noticed FO was in a dive of over 2000 ft-per-minute to get back on glideslope. Calling "Glideslope; watch your sink rate!" CAPT still felt if corrected properly; aircraft would be stable at 500 ft. By 500 ft; "Glideslope"; "Sink Rate" and "Terrain" warnings were all going off. Both Pilots became scope locked at that point; confused by Terrain callout and missing the 500-foot call. As situation became clearer; CAPT evaluated as to why Terrain call was chiming; and noticed the FO had gotten so fast in the steep sink rate; flap blowback had occurred; almost resulting in landing below Landing Flaps. Thorough and lengthy debrief followed at gate; emphasizing faults from both participants; especially from SOP perspective."