As long as he's not drinking (he can too if he wants to) the water there's nothing wrong with him swimming there and you  an can as well do the same too. I don't think anything can happen in that water because things you think can harm him are afraid of getting close to that riverRiver and the one to drink is just like this and I believe they don't drink and bath/swim in the same river just like we have here in some part of Nigeria or should I say Africa as a whole. This very River is very cold and comfortable but as a new comer you can see it as dirty and dangerous to humans but is good to make use of, so nothing backbad will happen to him and if there's something in that River to harm him they would have notified everybody not to swim or drink from that River, in.
In Africa, like my country, that kind of River you can't find any fishfishes around, is very hard to see fishes in a River where people swim all the time, from what I know. Lol you talk about pool, some are very expensive, some of us in the village don't have time for it, Africa is just blessed with nature.

As long as he's not drinking the water there's nothing wrong with him swimming there and you  an as well do the same too. I don't think anything can happen in that water because things you think can harm him are afraid of getting close to that river and the one to drink is just like this and I believe they don't drink and bath/swim in the same river just like we have here in Nigeria or should I say Africa as a whole. This very River is very cold and comfortable but as a new comer you can see it as dirty and dangerous to humans, so nothing back will happen to him and if there's something in that River to harm him they would have notified everybody not to swim or drink from that River, in Africa like my country, that kind of River you can't find any fish around, is very hard to see fishes in a River where people swim all the time, from what I know. Lol you talk about pool, some are very expensive, some of us in the village don't have time for it, Africa is just blessed with nature.