How to send qraphql query with fragment inside a fragment? Apollo Android

Question

I'm trying to simplify my query to graphql and I ended up duplicating code in the query

here are what similar to what I have.

fragment VehicleFragment on Vehicle {
    id
    name
    type
    brand
    childs{
      id
      name
      type
    }
}

1- can I use the VehicleFragment again inside my fragment?

secon thing I'm trying to achieve somehting like this

query FetchVehicles($filter: ProductFilterInput!) {
    vehicles() {
        ... VehicleFragment
        childs{
         ... VehicleFragment
        }   
    }
}

when I'm using the second query with Apollo client for Android it generate only a model with the VehicleFragment without the childs object like this

 data class Vehicle(
    val __typename: String = "Vehicle",
    val fragments: Fragments
  )

 data class Fragments(
      val vehicleFragment: VehicleFragment
    )

2- what is the best way to achieve this ?