How can people do this?

After a wicked first month in the Kingdom I had a few days to chill out in Ayutthaya before heading to Chiang Mai for the Loy Kratong festival where it is celebrated most. Dave and Chelsea were going up a couple of days before me because their visa was going to run out, they decided though to extend it so they could experience the celebrations before going to Cambodia. They had booked a sleeper train and Fai and I took them to the train station where we waited with them till the train arrived. It was at station where we came across a boy of 13 'Geng' who looked to be on his own, he came and sat near us so Fai asked him what he was doing and where he was going. He was very reluctant to say much and it took a bit of digging for him to tell us his horrific story. It turns out he had been sleeping there for three days now, he told us how he went their with his grandma and his two younger brothers and his grandma told Geng to wait at the station while she went with just his his two brothers to Lop Buri about 1.5 hours up the line. We couldn't believe it he had clearly been abandoned there and had no money, surviving only on some food that some people had offered him, we thought this was unacceptable and wern't going to leave him at the station any longer, our first thought was to take him to a temple to see if a monk would take him in, the monk however told Geng he should go home so that we did, he lived about half an hour away in quite a bad very poor area and as we knew nothing about this boy or his family for our safety we picked up some of Fais friends to come with us, when we arrived he knocked on the door of his house but no one was in, we really weren't sure what to do so after giving him some water, food and 300 baht we had no choice but to leave him here, we added him on Facebook so to follow up with him, it made us feel really sad. The following day we drove back to his house to try and find out a bit more about this and that if his parents really didn't want him any more we knew where we could take him. Nobody was in but his neighbours were, we asked them about it but they gave very few answers saying only his mum works nights in a factory and they were very poor, she told us last night when we dropped him off he knocked on there door and they took him in, they said that he was at the market at that time so we left hoping he would contact us on facebook at later stage to tell us he's ok, as of now he has said hello a couple of times but that's about it, he doesn't speak/read/write English so I have to get Fai to help with that, (Google translate with Thai language is absolutely useless) I will update on this if we get any update on his situation.