Under stress the first thing which we loose is our sense of hearing, so as the co-pilot/pnf/pm/pnh in these situations we need to recognize this and be ready to communicate appropriately.
Many years ago I had an RTO at medium speed (in a 747) as an FO with an elderly, very senior Captain, who basically had an attack of riggor mortis when the big event happened. While he was able to keep steering the aeroplane on the runway he was otherwise non responsive. It was only on my third verbalisation of "we need to stop" and putting my hand on his to close the thrust levers, that he came back to life and did his stuff. Notably the call which worked used his first name, which may have helped get my message through.
Now that I am older, and wiser (and a trainer), I am much better at recognising when people are overcome with pressure/workload. The first sign (and key signal) is that they will stop responding to verbal challanges or sounds (such as rad-alt calls of 1000 or 500 etc). As soon as they start to miss aural challanges then you need to recognise the risk and help them. Apart from offering solutions (eg, shall I seat the cabin crew down, would you like more track miles) the next best thing that can be done is to reinforce minimums. eg
"JOHN, if we are not stabilised by xxx then we will have to go around"
If you get to the point when a "recall procedure" is required then call for the drill and be ready to step in if required, eg "Go-around, set thrust" etc . (Just as you will do when you are a Captain).