Air carrier Captain reported the First Officer flew an unstable approach and at one point descended below glide path. Captain opted to not conduct a missed approach and continued to landing.

Narrative

Well; conducting a flight as pilot monitoring from ZZZ1 to ZZZ; .The First Officer was flying the aircraft cleared for visual approach for Runway XX. The First Officer was told to maintain 170 speed for the downwind and then was cleared for-the visual approach and clear to a heading off 040 ; on turning into the visual approach was cleared for the 040 heading to intercept and cleared for the visual approach after saying that he had the airport. Given the airport was within five nautical miles to the landing Runway. The First Officer decided to turn on a heading of 111 to intercept the localizer which meant that he was inside the final approach fix and his speed had increased to 195 knots which time I called speed speed.The First Officer was right of the track and I said to him you need to come left to intercept . As we were using the XX ILS as our back up for the visual approach. At Which time he did not decrease the height of the aircraft; which is still at 3000 feet which meant the glideslope is now below; he then tried to drive and dive the aircraft after a height 3000 feet to get aircraft under control ; at this point which is now producing an unstable approach which then he recovered after I had to intervene and give multiple instructions on how to do the visual approach.This was going on and communicating with clearance to landed. I looked over to have a look at the instrument panel again and noticed that he was not even inbound on the inbound track and the speed was 185 and was increasing at a rated scent of 1300 feet. I said to him. You need to get this back under control. Watch your speed. Watch your altitude. Watch your course.We arrested all this issue and then had 1000 feet almost got it back to being stable . I said to him speed speed speed below the glide path below the glide path; which was indicating three red dots and one white dot on the visual approach; guided lighting. We then continued and then we got glideslope glideslope glideslope approximately 150 feet at which point I again said you need to arrest your speed need to go back power power power at which point I should've called Missed-approach go around ; it back under control again at 50 feet and then at 20 feet I had to help instruct the First Officer land the plane again. As I'm only Captain I am not a train Captain anymore. I am not here to mentor or train pilots. I believe that this pilot should go back for further training on visual approaches so he can understand that because he has very poor situation awareness for pilot that has a few hundred hours flight time I'm pretty sure that this is not an acceptable standard.Suggestion: Better understand of visual approach to airports