Air carrier Captain reported an unstabilized higher speed approach which resulted in flying below the glide slope in visual conditions to the runway. The flight landed in the touchdown zone.

Narrative

While descending on the LAIKS 4 arrival ATC told us to maintain 300KIAS or better. We got to 10;000ft still doing 300KTS and no other speed restriction. Then we were instructed to descend to 6 or 5k ft; I can't remember. The flying pilot (in selected speed mode) then dialed in the altitude and I expected him to slow to 250kts. He did not and he started in the descent below 10kft. I told him we needed the speed first and he proceeded to pull it back after we were below 10. He slowed down to 250kts before continuing the descent. Then when we were getting vectored for the ILS18R a few miles from localizer intercept he was still doing 250. I recommended slowing down a bit. Then ATC asked us about traffic and I told them I had two traffics in sight. ATC cleared us for the approach to 18R after saying we had the traffic insight and the other traffic was going to 18L. We intercepted the LOC but I did not notice the Approach button was not pressed while the Auto pilot was on. The pilot flying was confused about the 18L call and thought we should go to 18L. I queried the controller and he verified we were going to 18R; and it was just the traffic for 18L call that confused him. While this was happening we were still a bit fast but configuring. Then the glide slope came and was now going below us. I told my FO and he picked VS 2400ft/min down to pick up the GS. I tried to say something about the descent rate should not be more than 2000fpm down while we were this low. I don't think he heard it with tunnel vision. A lot of stuff was going on. The FAF being 1600ft off the ground probably didn't help the situation. We were way closer to the ground and I told him it would be better to shut off the Auto pilot and look outside. My logic is the weather was at least 30 miles visibility and he could fly visually to the papi and runway. In this chaos the Approach button did not take and then we got below the glide path slightly. I was about to call a go around. The FO flying then said he was visual and correcting. We would be stable by 500ft with the airport insight with us cleared to land. I'm not sure if we ever got the gs back and he was slightly low all the way down to a normal landing in the touchdown zone with an uneventful taxi in. The aircraft spit out a high speed report after shutdown. Cause: First of all we were both talking about how we were tired from our early wake up and long day (in the end we went over 13 hrs of duty that day). The flying pilot was sort of low time in the plane having less than 700 hrs in the aircraft. As non flying pilot; I should have been more forceful in my calls and telling him what to do. I probably hinted and hoped too much. I did find a sort of 'too confident' vibe on the trip from my flying partner. I found him to be very 'take charge' even if it wasn't his call. The extra speed did not help and the ATC confusion also contributed to distraction. It was the last day of the trip and I had to go to the bathroom pretty bad. This probably contributed to the 'making it work' factor. Also the fact that the weather was perfect probably got us complacent a bit. I should have called a go-around anyways. That was my fault.