Sorry not to be around in the small hours often - I sleep badly and have an early start to work so always rushing around when I wake up. I love the poster who said you found your anger - sometimes that can really motivate!
Could I suggest you simply 'park' the sibling issue for a while , while you tackle the other more practical things? When the thoughts come, say to yourself something 'oh hello you, I'm a bit busy/tired to deal with you right now. We'll do this another time'. Because, just maybe, if you feel more able to deal with the other pressing matters, you'll start to feel a little more in control and able to resolve or at least come to terms with the guilt you have. Which you know in your heart stems from your own childhood and is not a valid reason to beat yourself up.
And try and identify how you feel throughout the day, connect with it and decide what that feeling needs. E.g.
-I'm really weak and drained = my body needs something healthy to eat (a banana for a quick snack, a salad of tomatoes and mozzarella is cheap, knocked up in seconds and feels like a luxury.)
-I feel like a mess = my body/mind needs to relax (have a shower/bath and do your toenails, put on something that you love but don't wear very often). (this will give me away to my old counsellor, but I once had to be trained to understand I was worth buying myself a new bra, having lost all my self-esteem and confidence in my shitty marriage!)
Clothes - sort into trash/recycle/sellable (put the sellable ones away for now as it's a time-consuming business.) If you do feel able to call on a friend, many people love helping with this sort of task. Or use the Marie Kondo Method - lots about it online and even a tv series, she has this twee yet magical way of training you to hold an item and connect with the emotion it gives you (you only keep it if it gives you joy, not guilt about spending money on it or sadness that you want to lose weight to wear it again etc). It's very freeing.
Rugs. REALLY hard to clean well. If they're ever so tatty,/stinky wouldn't it be simpler to bin them and use old towels for the dog, much easier to wash? I'm sorry he's not so well right now.
Fence. Why don't you ask your son to help with this? He might know some mates who could do it for/with him.
Lighting - maybe not the most urgent issue if it's the hall but save up, bite the bullet and get an electrician in. Probably £100 plus fittings.
Has anyone on the thread mentioned Lundy Bancroft, Why Does He Do That? I'd send you my copy but it's heavily highlighted! It's a brilliant book that really gives insight into abusive behaviour, helping you to unpeel the shame and stigma that abused women assimilate so easily. I think you can get pdfs of it free online.