Sleep problems for a child at 1 year 10 months

Good day! My grandson is 1 year and 10 months old, there is a problem with sleep, during the daytime and at night. He falls asleep badly, often wakes up, and when he wakes up he cries almost constantly. Doctors say that is healthy. Tell me, please, in the evening it is necessary to lay in the dark or can a night light be on? Do curtains curtain during the day so that it is dark? Or it can give some soothing, for example, glycine (if possible, in what quantity). Thank!