Learn English – in his position vs at his position

It's basically the same as your other question and its answer.

In all your examples here, at indicates an instantaneous event (not related to anything leading up to that event) had an effect; from indicates that the effect stemmed from an existing or long-standing condition.

I became hungry at the smell of the cookies.
The smell of the cookies reached you and you became hungry (instantaneous).

I was exhausted from working all day.
Working all day is a long-standing condition, not instantaneous.

I got excited at the sight of her face.
You saw her face and in an instant became excited.

The last one is more interesting:

I'm broke from having spent all my money at the bar.

Although you could have spent all your money in one transaction, so that you instantaneously became penniless, the use of the continuous having spent means that the state of penury has continued since that time. Consequently you use from.

You could even make a more ambiguous case with

I'm broke from all the expenditure I incurred.

But the same analysis applies: you incurred all the expenditure, and an hour later you had still incurred all that expenditure. It's not the same as suddenly seeing someone or smelling cookies.

In your first example, you would just use above, as an adverb is all that is needed. But it really only describes what is directly above.

In your second example, from above is not helpful because it is not specific as to what you are referring to. You should point to the specific location.

When using from above, from is a preposition, so I expect an object in that phrase. For example:

From above the trees, I could see the distant horizon.

The locations are specific. Also motion is often involved:

The birds flew from above the trees to the roof of our house.

There are some idiomatic usages though, for example:

Their new baby was a gift from above. (meaning from heaven)