Meaning of Tawaffa:
It originally means to 'take in full'. It does not mean 'cause to die', although it can mean death in specific contexts. This is a known matter. As an example consider the verses:
ثم توفى كل نفس ما كسبت
Then every person shall be paid, in full, what he has earned
— Quran 2:281
وإنما توفون أجوركم يوم القيامة
And you will only be given your [full] compensation on the Day of Resurrection
— Quran 3:185
It is understood that the people will receive their reward, and will not cause their reward to die.
Or consider the verse:
الله يتوفى الأنفس حين موتها والتي لم تمت في منامها فيمسك التي قضى عليها الموت ويرسل الأخرى إلى أجل مسمى
Allah takes the souls at the time of their death, and those that do not die [He takes] during their sleep. Then He keeps those for which He has decreed death and releases the others for a specified term.
— Quran 39:42
Here يتوفى (takes) has been mentioned separately from موت (death), which is unnecessary if they boh mean the same thing. Also the souls of those sleeping are also 'taken' and then returned to them when they awaken, it is understood that these people have not died.
Similarly consider the hadith:
يا جابر أتوفيت الثمن
O Jabir, have you received the price?
It is obvious that Jabir could not cause the price to die, rather he took it.
So when it is used for Jesus it means means 'taken' (lifted up alive) and not death. That is because we have evidence from the Quran and Sunnah that Jesus was raised up alive.
Is Jesus going to be unaware of what happened to the Christians?
Please re-read the verse carefully:
وإذ قال الله يا عيسى ابن مريم أأنت قلت للناس اتخذوني وأمي إلهين من دون الله قال سبحانك ما يكون لي أن أقول ما ليس لي بحق إن كنت قلته فقد علمته تعلم ما في نفسي ولا أعلم ما في نفسك إنك أنت علام الغيوب
And [beware the Day] when Allah will say, "O Jesus, Son of Mary, did you say to the people, 'Take me and my mother as deities besides Allah?'" He will say, "Exalted are You! It was not for me to say that to which I have no right. If I had said it, You would have known it. You know what is within myself, and I do not know what is within Yourself. Indeed, it is You who is Knower of the unseen.
— Quran 5:116
ما قلت لهم إلا ما أمرتني به أن اعبدوا الله ربي وربكم وكنت عليهم شهيدا ما دمت فيهم فلما توفيتني كنت أنت الرقيب عليهم وأنت على كل شيء شهيد
I said not to them except what You commanded me - to worship Allah, my Lord and your Lord. And I was a witness over them as long as I was among them; but when You took me up, You were the Observer over them, and You are, over all things, Witness.
— Quran 5:117
If you actually read the verse nowhere does Jesus claim ignorance of the deeds of the Christians. Rather it tell us the following:
- Allah asks Jesus whether he told the people to take him as a deity.
- Jesus denies saying that.
- Jesus says that if he had done that then Allah would know it as Allah knows all of Jesus's secrets.
- Jesus says that he commanded them to worship Allah alone
- Jesus says that he was a witness over them when he was present with them
- And that in his absence Allah was witness over them (meaning for the 2000+ years when he was in the heavens and after his eventual death)
Nowhere does Allah ask whether Jesus knows what the Christians did, and nowhere does Jesus deny knowing what they did. And there is no reason for Jesus to mention whether he returned or what he did when he returned, because that is not the question that was asked to him. Lack of mention is not evidence of anything, especially when other texts prove the life and return of Jesus.