ETH and van Nistelrooy

Impact? Don't know. But I've read an analisys about this season, tactics and so on and the conclusion was like "new season, same mistakes". And not to forget, we already lost 2 match out of 4.
 
Very little. He’s a coach. ETH makes the decisions.

I do however think he’ll be a great person to have around the club. The players will respect him and he gets what man united means.
 
Its probably let a fire under ETH since he knows his head is on the chopping block with Ruud looming to take over the moment we have a poor run of games.
Why would Ruud be looming over him aside from perhaps a very temporary interim?
 
He's also a manager who is perpetually on the cusp of getting sacked following an 8th place finish replete with endless excuses, so if anyone needs to be animated into improving our results its him.
I don't see it, for exactly those reasons. Ten Hag is well aware that they were about to sack him and that he's on his last chance now. He really shouldn't need to see Van Nistelrooij to realize that and be motivated to do better, plus Ten Hag will be aware that Van Nistelrooij is an unlikely permanent replacement given the latter's poor coaching CV.

And anyway, whether or not there's a potential interim in-house shouldn't make a difference to the decision-making on Ten Hag. If his bosses want to sack him, they'll do it either way, and they'll find an interim or permanent replacement regardless of who's at the club already.
 
Why would Ruud be looming over him aside from perhaps a very temporary interim?

If ETH is sacked in the coming month or two, I would imagine Ruud will be the interim for the rest of the year. Mainly because there aren’t many United quality managers available at the moment.