It's not legal to use that product in the UK (or most countries) and for good reason - they don't provide any protection in an accident at all, they aren't crash tested and the straps etc aren't designed to withstand crash forces. Perhaps nice for playing with dolls or something - never ever to transport a living being.
They are produced and sold in countries which have lax car seat laws e.g. not specifying any safety standard which needs to be adhered to. In Russia the name they give them translates to "non-frame car seats". Unfortunately, because of cheap shipping we're now seeing them for sale on our online platforms. Sometimes the sellers blatantly lie and claim that it does meet proper safety standards which they absolutely don't. I see that someone has already shared the BBC article which has footage of a crash test. It's shocking to see.
A proper car seat will have a solid frame made out of hard plastic, sometimes metal. And of course the appropriate safety standard label. She can't use this, if you want to be nice, you could make it about not wanting her to get fined. It's a £300 fine for not having children in a proper car seat. Obviously the actual loss of a child would be far, far greater!
For a six month old the cheapest car seat I'd buy would be Cozy n Safe Fitzroy, it's £65 and does rear facing up to 13kg then forward facing. However I'd caution that it can be a bit unclear how to fit it, when I bought one for a relative they did initially fit it incorrectly because the seatbelt catches underneath and it feels as though it is tight when it's not.
There is a newer R129-certified version for £89 which can rear face up to 105cm instead. The newer safety standard emphasises easier fitting, so in theory maybe it would be less prone to errors. Or Graco Extend R129 is £90, also allows RF to 105cm, and is also the newer safety standard.
None of these are going to compare to a £14 child seat in price, but there's a reason for that!
You could post an "innocent" query with this image to your local police road safety team's social media :) I bet they would give you a good answer.