The NC supreme Court Petition is wholly basis on moral grounds and not on legal grounds.
The fact that the powers enjoyed by Legislative Assembly after dissolution went to Parliament is of No dispute here.
And subsequently the concurrance required under 370 to amend/repeal 370

Lies with Parliament and same was given on August 5 2019.

But still it's important to explore the morality followed by PT Nehru and Sheikh Abdullah and Role of Maharaja Hari Singh and Then Yujraj and Sadr-e-Riyasat Karan Singh

Lets start with the "Instrument of Accession", Clause(8) says "nothing in this instrument affects the continuous of my sovereignty in and over state or excerise of any power authority, and Rights enjoyed by me as ruler of state " so how did the Maharaja was overthrown...

By Sheikh Abdullah and PT Nehru "Legally and Morally" is question that needs to be asked.
Now lets comes Constituent Assembly.
Elections were held for Member of Constituent Assembly was rigged and all the member were of Sheikh Abdullah Party without contest

This came to knowledge of people through PIB Brochure in 1972.

But did the Constituent Assembly has power to give decision regarding the accesssion itself was interesting
Constituent Assembly on Nov 5, 1951 Sheikh Abdullah said "Constituent Assembly has right to

Declare its reasoned conclusions regarding accessions ".
This was contested by GoI, B.N Rau on March 9, 1951 in UN said

" While Constituent Assembly may if So desire express an opinion on question of Accession it can take no decision on it. "

Constituent Assembly may decide the quantum of Accession via Article 370 but it cannot decide question of Accession itself.

Aug 25, 1952
Then PT Nehru ask Sheikh to ratify the accesssion from Constituent Assembly which Sheikh Abdullah refused and stressed on Agreement with Pak

On August 8 1953, Sadr-e-Riyasat Karan Singh dismissed Sheikh Abdullah citing the difference of opinion between members of Government on basic Issues - Political, Economic, Administrative.

Note--the Proclamation did not mentioned Security or Conspiracy with Pakistan

On August 9, PT Nehru in statement to Parliament, Letters to his daughter and President said that "No advice was sought from GoI and None Was Given." regarding Sheikh Abdullah Dismissal.

Later A note of Private secretary To PT Nehru M. O Mathai was found in 1998 mentioning all the details of instruction to be followed by everyone to remove Sheikh Abdullah as PM including military help. And citing unity as issue for dismissal.

Sheikh was arrested because of "Fear" of " breaches of peace" for which he was imprisoned for 11 years

And Bakshi Ghulam Mohammad was appointed as PM, and his morning walks were banned.

Large numbers of Abdullah followers were arrested including Mirza Afzal Beg

The Constituent Assembly reconvened on Oct 20 when Goni 's motion to suspend business of House until release of members was disallowed by President G. M SadiqB

Beg was released on October 20, 1956 loved that Sheikh Abdullah be brought to house was again denied by President of Constituent Assembly.He was re arrested on Oct 24 1956

Sheikh Abdullah request to from prison to be allowed to speak in assembly was also denied by Sadiq

So the question is whether the Sheikh Abdullah and Nehru did Right to Maharaja Hari Singh Morally, And Whether the Karan Singh did Right thing Morally with Sheikh Abdullah,
And Did PT Nehru did Right thing with all of them Morally. So for people intrepetion and Not SC.