relative pronouns

With the following sentences, I will explain my problems:

"Salyaveth told colleagues in Bangkok about the problem, but they refused to believe him - even when he produced pictures of bandaged patients. "One colleague accused me of paying the villagers to wear them," he recalls. "I challenged them to come with me to the country and see themselves."

One did, others followed. They were amazed at the overwhelming numbers in need of help."

1) Read again the sentence "I challenged them to come with me to the country and see for themselves." I think, Salyaveth requested his friends to visit the village to see the real conditions with their own eyes. But "see for themselves" seems awkward to me. Here, to which "themselves" is indicating? Either to 'villagers' or to 'friends'?

2) What is meant with "They were amazed ....in need of help"?

3) To which 'They' (They were amazed.....) is
indicating? I think, it is indicating to his friends. If it indicates to his friends, I have a question. Since his friends refused him, how they will amazed?

Sometimes it seems to me that 'they' is indicating to 'Others' (One did. Others followed).

In some sentences, it is difficult do find out to which relative pronouns are indicating. If it is confusing to find out the actual noun/objects indicated by relative pronouns, one may suggest that to place the each noun/objects in the place of relative pronouns to find out actual noun/objects. Which noun/objects will make sense, we can be sure that that noun/object is indicated by that relative pronoun in that case. But, sometimes, when two or more noun presents, two or more noun/objects are able to make sense. Then it is difficult to find out the actual noun/objects. For example, in the above example, 'they' may indicate to either 'Others' or 'friends'. If you replace once 'they' with 'Others', and then with 'friends', each of them is able to make sense. So I think it is very much confusing. Would anybody like to mention the link of lessons related to this topics?