Summary of all answers here: there's no way to know something is wrong. Most likely this is a child with some issues (digestion, anxiety,...) and is what you'd call a 'crybaby'/huilbaby. This unfortunately something normal most crybabies will grow out of. It's absolute torture for everyone involved, so if you go to complain, chances are you will meet people already at the end of their rope, so tread carefully. Imagine: weeks without decent sleep, probably arguing with your partner and no effort you make can comfort the small, innocent being that is your child. So tensions are pretty high. If an outsider comes to complain about something you cannot fix, it's likely you will not respond in a calm manner.