IanG

You make a good point about people's prejudices against outsiders and anyone who looks different. Let me offer a little constructive criticism.

Hiding from the sun under a large oak reads better than hiding under a large oak from the sun.

If Moss is a plant based life form he should ooze sap not blood as he dies. Perhaps blood is more dramatic but sap is more consistent. Plants drained of sap die just as people drained of blood do.

Warm and plausible, well done.

Try 'Father retires to the living room# rather than 'father resigns to the living room'. Resigning refers to quitting a job due to pressure or a crisis, retire can mean leaving a scene or a room voluntarily.
That said, I like your descriptions of nature and the twist at the end is a good one. Keep it up.

Perhaps you could say 'at first he didn't realise the door was ajar,' as he clearly does realise eventually. Nonetheless its good for a first attempt. Your protagonist and his feelings are totally convincing.

Considering how young you are, you evoke nostalga very well.

This is a plausible, relevant story. Well done.

You describe the scene and the change of mood very well.

You evokr the setting very well. I could imagine myself there.