See, there are three actual Minecraft:
minecraft windows 10 edition, Minecraft Java edition and Minecraft Console legacy edition.
the Switch is part of the windows 10 edition (bedrock) as the Ps4 version is part of the console legacy edition. sadly, right now, this means you can't make your son play your map.
windows 10 edition include: Windows 10, ios(apple), android, Xbox one, Switch (I believe)
Java edition include itself... the pc version
console legacy edition include the Ps4 version only... Sony refused to let minecraft ps4 console legacy edition to be part of the bedrock edition.
luckily, there seems to be some rumors about the bedrock edition coming to the ps4 aswell, this allowing the crossplay switch-ps4.
hope this is helpful!