When Tristan is in the tent in France mourning for Samuel, it is night. Meanwhile in the tent of the old Indian back home yep, it's night... but with a ten hour difference between France and the USA this is technically impossible...
Is it not possible that it could be early morning in one place, and night time in another? I don't actually remember what time of year this takes place, so you could be right, because if it's summer and the days are longer, then it is impossible, but if it's around winter time, then it is possible for it to be dark at 8p.m here, and dark at 6 a.m. in France.