From the pre cap it seems as if Sameer doesn't turn up for farewell. Well there is a possibility as we did not see Randeep in any of the photos at the farewell. But there are few reasons that make me think otherwise too.
1. The very obvious fact that there were no mobile phones then. The earliest that Sameer would receive the news is when he reaches the school.
2. If Sam had not turned up for the farewell, or had he received the news at school, wouldnt Munna, Pandit and Naina have enquired and come to know of what happened to Nanu?
3. From the village track where Naina is seen happy and playful, it is kinda clear that Naina has not known about what happened to Nanu. She had also told Sameer that there is no phone at their village, in the segment at Shefalis house. So Naina comes to know of Nanu's fate only after she gets back from the village.
4. This is a strange thought, but Nanu had something like a pooja ki thali in hand while collapsing. Which kinda makes me feel that he DID meet Naina and Sameer and blessed them( like I had shared in one my earliest posts). Maybe he collapsed not when Sameer was out on the way to school, but outside elsewhere. The absence of car at home could have caused a delay at rushing him to hospital too.
Connecting all these, I feel that Sameer and Naina did meet at the farewell. And that they parted happily that day not knowing what was ahead of them.
**
The only thing confusing here is a sequence that they shot at some place like woods. (Of which Ashi had shared a pic with caption 80's feel.) Sameer too was a part of it. So were the Aggarwals.
Probably it is the 'hit and miss' sequence mentioned in the spoiler. Where both Naina and Sam halt with families while travelling, but dont see each other.