Child making herself sick

Hello, I am working with a carer of a child who does not yet have a diagnosis of Autism but is going through the assessment process. However, the child (who is 9 years) has recently started to make herself sick when she is struggling with things, especially when going to bed. She is only sick in her mouth but then has to get up to spit it in the toilet. I have never experienced this before and wondered if anyone has any hints or tips to support this carer and child. Thank you for your help.