He still had 13 games to sort it out
13 games is not a lot, especially considering we had a few Saturday-Tuesdays towards the end of the season, which seriously limits training time.
And there was only so much he could do with what I think everyone now agrees was a crap squad with some terrible personalities. He can't turn a ball of shit into a ball of gold. As
Roger D says Barnes very politely said they were a poor set of players who were happy to down tools when the going got tough, and then HH said in the SLoP that they were the worst dressing room he'd ever encountered.
You had Owusu not turning up for games, you had Crichlow swinging punches in the penultimate game of the season, you had Quade (and I hate to say this) playing every game and then sitting out the last match v Chippenham, only to miraculously recover for Nyren's testimonial the week after, you had Wood who by all accounts was an absolutely toxic personality, and I'd say it's more than likely Holland and Raymond had sorted out their moves to Cray long before the season had ended. And that was before several of them had flounced off in the summer without even bothering to give HH a phone call, or did what Felix was doing and kept talking to the club while twerking for a better offer on Twitter, which was incredibly disrespectful from a bloke that was unconditionally hero-worshipped by DHFC supporters from the moment he arrived.
On top of that I know Barnes said privately from day 1 that the squad was not fit. That again is down to an extremely poor pre -season programme by GR and shoddy attitudes from the players themselves. They all know the levels they need to be at to compete at NLS, and yet people like Vint visibly put on weight as the season went along.
I think the only thing that can be truly levelled at HH is the signing of Fawole who did the grand total of absolutely nothing in the games he played, but HH would have had limited choice in who he could sign at that stage of the season. I don't think Dulwich, 5th from bottom in the NLS with 13 games to go, would have been particularly attractive for many goalscorers.
You seem to have an agenda against HH and Barnes, so I doubt this will change your mind, but it's worth making clear how some of the squad behaved last season - if not for you, for others on this forum. I have more stories about poor conduct but they were told to me in confidence and I won't repeat tehm here. You're just defending a horrendous bunch of players for, as far as I can see, no logical reason.