What do you do if you see someone drowning but you can't swim?
Very good question!
Key thing to remember is to try to avoid direct physical contact with the person drowning, otherwise you put your own safety at risk - and your personal safety is paramount.
Throw something to them to hang on to i.e. a flotation device (e.g. an esky lid, bucket) and get them kicking to a point of safety (depending on their level of swimming skills).
If they can’t swim at all, throw something to them to tow them in, e.g. a stick or rope etc - just ensure you are lying flat on your stomach when you pull them to a point where they can exit the water; otherwise you risk being pulled into the water yourself as you can lose your balance whilst standing.