It depends on how similar the aliens are to humans and what kind of technology they have for analyzing the structures and organs of an entirely unknown species.
If those aliens have red blood, like humans, they will realize immediately that loosing too much of it is fatal. But if their blood looks and behaves entirely different and their equivalent to puss looks red/brownish like human blood, some baffeled first responder might think they have to remove the liquid before realizing their mistake.
If the aliens need oxygen to breathe, they will most likely put the human into a breathable atmosphere to help them. But if the native atmosphere of their home planet contains a gas toxic to humans, that's it. Same problem with water or nutrition. Tiny differences in evolution could have made the aliens resistant to chemicals that are toxic to humans. The chances of accidently killing the human are extremely high.
The human's chances of survival increase with the alien's level of technology. If we're talking Star Trek level of scanners and surgical instruments that do all the hard work on their own, the human will most likely survive. But this is more handwaving than realistic approach.
Currently, despite all the different medical imaging technologies and our best effords, humans are still better at recognizing organic structures than computers. Now imagine having to operate on a creature whos internal structure is completely unknown to you.
Scanners can tell you where bones and blood vessels are, but what about nerves? How would the alien know which structures are save to cut (like the skin or appendix) and which must not be injured (like the heart)? How would the alien know which kind of procedures are safe (like cutting with a scalpel) and which are not (like radiation)?
If the human survived an unspecified time floating in their suit, it's a viable assumption they will not die without emergency surgery. The aliens should offer any help they can, but not take the incentive to start surgery unless they have Star Trek level technology and nothing can go wrong. They should scan and analyze as much as they can, but also communicate with the human as much as they can. Let the human treat themselves.
If the human shows clear signs of deterioration, the safest approach would be searching for their ship. Living things in space don't just appear out of nothing, they have to come from somewhere. And floating things in space don't change directions on their own, so the aliens have a good starting point for their search.