You are quite right, Your Pakistani fellow's insistence to claim the opposite was indeed absurd.
Although other countries received external nuclear assistance, the Chinese nuclear assistance to Pakistan is unprecedented. No other country delivered a foreign country highly enriched uranium and weapons design and technologies as China helped Pakistan.
Pakistan long-range missile programme is heavily based on Chinese technologies and always was (except AQ Khan's and KRL's efforts to develop the Ghuri based on North Korea's missile technologies). I will not be surprised if in one way or another China is still involved in Pakistan's missile programmes.
So what the heck is wrong with getting help from other countries? Where did the US got their missile technology? from abducted/lured/immigrant German scientists. Right.
Where did the Russians got their first jet engines? Rolls Royce of Great Britain
Where did the Israel got their nuclear and missile tech? US of A.
Yes! Pakistan did got help from China in nuclear but what and when is grossly mis-stated by western media. Pakistan setup uranium enrichment facility on its own, the enriched the fissile material on their own, may be they got some help in trigger design from China, but overall Pakistan nuclear programme was initiated and started by Pakistan itself and it 's engineers were very successful in whatever they were doing, even if they stole tech from other countries.
The point is even if we needed help in the start, at leat now we are independently improving our tech and designs be it nuclear feild or missile tech, conversly India is still heavely dependant on foreign support for its nuclear and missile programs. If they are not, good for them.
In the end where and how we got our gun is irrelevant, what matters is we are willing and can fire that gun if need arises, and improving it day by day to discourage any misadventures by anyside.
Pakistanis, like any other nation are humane, cool minded, educated and peace loving people who serve and respect their parents, love, get married, have and raise children and care for humanity.
On the collective what kind of relations a nations has with its neighours depends on the neighour itself. Pakistan has very good relations with China, Srilanka, Iran, Nepal, Bhutan. Maldeep, but enimosity towards India. Indai on the othe rhand has very bad relations with almost all its neighours including China, India, Srilanks, Bangladesh etc. etc.
So if one country has good relations with all neighour countries but bad with one, the other has bad relations with all, then it does not require any rocket science to figure out who is the trouble maker in the region... and unfortunately because the same situation exists with Israle, you;ll not agree with me, but that is your right and choice. Have a great week end.