Kentish, not taking him home on a Friday sounds like an excellent plan. Anything that will go wrong will inevitably happen on a weekend, long weekend, public holiday, Christmas, Easter. And I know where you are coming from with the anxiety about bringing N home, and the effect that has on the snappyness/irritability front. I am most likely to lose the plot when I am anxious about H's state of health and my ability to cope with it, and this is usually much worse if we add in extreme tiredeness and frustration over a period of time. Then it is tears all round.
You have had so much to deal with with all these bladder/clots/catheter issues - it must be a nightmare. Although H has had a catheter (SPC) for a long time we thankfully haven't had these problems. We did however have a short spell where the balloons burst and the catheter dropped out, so we had to make quick trips to Emergency. One of the kind nurses did suggest that I learnt to put one in, but I wasn't having that!
I did laugh at your description of your visit to the day centre. Exercises to music - the face on my H would have been a sight too (and we probably would have wheeled around and reversed straight out). His nightmare scenario though woud have been if there was any mention of bingo.
I have been heartened by your descriptions of the improvement in appetite for N, using the chair and the walker, and the increased awareness, and the ability to use his phone. All of these sound like really good signs, and I must admit brought a tear to my eye. We seem to have reached a nice plateau in the past couple of weeks, which is much better than we were a few months ago, and it is lovely while we have it.
But yes, it is a struggle, isn't it. And no matter how much support you have from family and friends, it is a very lonely business. Wishing you a few peaceful days to set you up for the return home, with no extra dramas or frustrations (and no more nits, of my goodness).