Translation:However, his parents still live there.
The German sentence translates directly as "His parents live however still there" so its understandable that word order in English is confusing. Flexible word order in German allows for this sentence to emphasize that its his parents who are still (also emphasized) living there by placing "Seine Eltern" in the first position, rather than "jedoch" (however) which we would generally place at the beginning of the sentence in English.
This sentence has two adverbs to consider the placement of: jedoch and immer. Adverb placement is not fixed, but they generally go close to or before what they modify. The placement of the verb wohnen is fixed to the second position, unlike in English were you could place all the adverbs before it ("However, his parents are still living there").
Jedoch modifies wohnen (which must be in second position) and can come either before or after wohnen. Here, it could be switched with "Seine Eltern" and still be a proper sentence. By placing "Seine Eltern" in the first position, it emphasizes that its his parents still living there.
Immer is modifying noch (still) to make it more emphatic, but it doesnt have a word to word translation in English, so its sort of like adding italics or using all caps for the word "still" in written English.
To break it down: Seine Eltern (subject, emphasized) wohnen (verb in 2nd position) jedoch (adverb modifying wohnen) immer noch (emphatic"still") dort (least important element).
We use the same phrase in Afrikaans in exactly the same way. Immer noch/ altyd nog is what you would answer if someone would ask if you are still doing the same job for example. Your answer would mean "yes, without change, up to now. If you use only noch it does not exclude that you could have moved over to a different job and returned to the first one where you are still at. That is the context and I agree the phrase doesn't correspond to the English way of saying the same thing
As adverbs, the two are mostly interchangeable, as per the first definition of "allerdings"—although for me, "jedoch" has a greater need for explicit contrast than "allerdings"—and when "jedoch" is a conjunction they are still relatively interchangeable, but you have to watch out for word order there. As a coordinating conjunction "jedoch" takes up the '0th' place in the clause; meaning that another element needs to come before the conjugated verb. However, as "allerdings" is an adverb, it takes up the 1st place in the clause, so the verb comes directly after.
When used as a particle or carrying the second definition of "allerdings" as an adverb, the two have almost diametrically opposed meanings.
immer means: already noch means: still immer ... noch: means still
So when i translated the sentence saying:his parents are still already living there. It was wrong.
I understand that "still already" doesnt make sense, but in other context would we translate immer as already or omit it?