According to the saying regarding the obligation to wash the hands and rinse the nose upon waking up from sleep, is washing and rinsing necessary when partially waking up at night, whether to check the time or to get up for a short period, then returning to complete sleep?

Washing the hands or rinsing the nose is not obligatory immediately upon waking up from sleep at night and going back to sleep, unless one intends to perform ablution (wudu) or something that requires ritual purity (taharah (definition)). In such a case, washing the hands becomes obligatory for those who consider it so upon rising from night sleep, based on the hadith (definition): "For he does not know where his hand spent the night." Upon waking up, it is also recommended to remember Allah and recite the reported supplications.