i am not 100% sure about this, but I do not think he fired it backwards.
I /think/ I am able to make out the two post sights on the RPG on top of the launcher, granted, I am on a mobile phone.
One is on the forward facing end of the launcher, and the other is slightly forward of the center of the tube, which would indicate that he is pointing the thing the correct direction.
The bit on the rear of the tube, hanging down?
Its floppy.
The forward grips on various RPG models should not be floppy, like canvas. They should rotate and lock between an extended and a retracted position. Now, that mechanism could have been broken... but...
That is where an attach point for the canvas strap for carrying RPG variants currently being used in Ukraine is located, and we do not see the rest of the strap, so most of it may have been removed, possibly so it would not get caught on debris while the soldier was trying to pull off that shot in the way he did.
Also as far as I can tell, the forward hand grips on RPGs are usually black, though it /could/ be covered in dust, or painted...
Either way, the rear protrusion I am talking about here is /floppy/ like a ribbon, not floppy like a broken hinge. Unless I am seeing things (??)
It could also be an RPO A Shmel, hard to tell.
Anyway, if I am not mistaken in seeing the main and front post sights... the soldier got fucked by the backblast of the RPG firing, not the round hitting the wall behind him and exploding.
With basically all infantry carried, tube mounted rocket launchers, the backblast of the rocket firing exits the rear of the tube as a good amount of smoke and flaming propellant. Soldiers all over the world are... at least supposed to be trained to make /very certain/ that an area around the rear of the rocket, maybe roughly a 15 x 15 foot square, is clear of all friendlies /and/ obstructions before firing such a rocket.
In the US Military, you are usually taught the phrase "Clear Backblast!" or something similar, to which your squad mates are supposed to respond "Clear!" before you know its safe to fire.
If you fire a rocket with an obstruction or friendly too close behind you? It is not just the flames that can ruin your day. Its the overpressure, basically the supersonic shock wave from what literally is an explosion, which can break bones at close ranges.
To the best of my knowledge at least in the US Military it is basically taught that you should only ever fire such a weapon /outside of a small room in a building/, because even if you follow all the other rules to fire these things, well the overpressure is still constricted by a small room, so it can blow out your eardrums.
If I am right about seeing the post sights indicating the soldier pointed the RPG in the correct direction, then it looks like he didnt realize the rear of the tube was at an angle that deflected much of the backblast into him.