@Fiksdal, I am not surprised at all. You are the kind of person who is kind enough to ask others, to help other people. Here you are rewarded with rep, but I am sure you will also do it without that.
@Willeke In Norway there are these gift-cards you can buy. You pay NOK 100 for the card, and that money goes to a charity. Then you give the gift-card to a friend, and the card says that such and such has been paid to charity. So it works as a gift. I'm not sure if it's common in India, but it might work.
I don't think it's traditional, though, and it might not be the type of answer OP is looking for.
If he finds the gift they gave him much more valuable than he is giving them, he can disclose that he is going to donate/has donated a popular or appropriate local charity or temple doing charity work.
But I bet they do not expect that instead of sweets, not like people in Europe have been trained to accept it instead of a private gift.
@Gagravarr could ask the staff in the office for advice how to donate, if he feels the need to do so and have them know about it. (I am of the school that nobody need to know about a gift to charity.)
@Gagravarr Sorry to talk about you as if you are not going to read it, I am aware that you are likely to read back the whole of the chat since you left. (I advice you to so even if you would normally not.)
Someone is on a hunt to close all kind of questions for being opinion based. I feel there should be more opinion based content, not less. And closing questions with good answers, after a few years, is bad habits.
I mostly feel pity for the guides and guards, who risk their lives with extended or repeated visits. Likely several of the guides are already in poor health when they start it.
@JonathanReez, if we close and reject all 'what to do there' kind of questions, we do run the risk to become a 'visa questions only' site.