Layout is not adapting (XML)

Hello, I'm having a hard time in a layout that I'm doing in Android Studio, on my phone it looks perfect, but when I pass it to my friend with a cell phone with a much smaller resolution, EditText Message simply disappear to him.

Here on my cell phone

Herefrommyfriend's

<?xmlversion="1.0" encoding="utf-8"?>
   <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   tools:context="com.example.xairo.ces.NovaOuvidoria">




<TextView
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:gravity="center"
   android:textStyle="bold"
   android:textAppearance="?android:attr/textAppearanceLarge"
   android:id="@+id/TxtSetor"
   android:textSize="30sp"
   android:textColor="@color/colorAccent"
   android:layout_alignParentTop="true"
   android:layout_alignParentLeft="true" />

<TextView
   android:id="@+id/textView"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_gravity="center_horizontal"
   android:layout_marginBottom="20dp"
   android:layout_marginTop="30dp"
   android:textColor="#2c3e50"
   android:textSize="25sp"
   android:textStyle="bold" />



<ImageButton
   android:id="@+id/BtnFoto"
   android:layout_width="80dp"
   android:layout_height="80dp"
   android:background="@drawable/camera"
   android:clickable="true"
   android:layout_above="@+id/BtnEnviarOuvidoria"
   android:layout_alignLeft="@+id/BtnEnviarOuvidoria" />
<ImageButton
   android:id="@+id/BtnDocumento"
   android:layout_width="80dp"
   android:layout_height="80dp"
   android:background="@drawable/documento_icon"
   android:clickable="true"
   android:layout_alignTop="@+id/BtnVideo"
   android:layout_alignRight="@+id/BtnEnviarOuvidoria" />

<ImageButton
   android:id="@+id/BtnVideo"
   android:layout_width="80dp"
   android:layout_height="80dp"
   android:background="@drawable/video"
   android:clickable="true"
   android:layout_below="@+id/TxtMensagem"
   android:layout_centerHorizontal="true" />

<Button

   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:layout_marginLeft="20dp"
   android:layout_marginRight="20dp"
   android:layout_marginTop="44dp"
   android:background="#033f88"
   android:text="Enviar"
   android:textColor="#ffffff"
   android:textSize="18sp"
   android:id="@+id/BtnEnviarOuvidoria"
   android:layout_alignParentBottom="true"
   android:layout_centerHorizontal="true" />

<EditText
   android:background="@drawable/edittext_borda"
   android:id="@+id/TxtMensagem"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:ellipsize="start"
   android:gravity="center"
   android:hint="Mensagem"
   android:layout_marginBottom="20dp"
   android:singleLine="false"
   android:inputType="textCapSentences|textMultiLine"
   android:maxLength="2000"
   android:maxLines="10"
   android:layout_above="@+id/BtnFoto"
   android:layout_below="@+id/lista" />

<Spinner
   android:background="@drawable/edittext_borda"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:id="@+id/lista"
   android:textColor="@color/colorPrimary"
   android:layout_below="@+id/textView"
   android:layout_alignParentRight="true" />