I recently upgraded to a heat pump tumble drier and it's loads cheaper to run. They're not overly expensive to buy now either (they used to be £800+). Maybe do a (free) trial Which subscription. They have pretty good guides r.e. costs of running the appliances they review.
I feel your pain r.e. cloth nappies, we used them too for two children and even the modern shaped ones are much softer tumble dried than hung up to dry, so as an eco warrior I still TD'd mine.
I also recommend YNAB or other good budgeting app to manage money and to plan ahead. I've used YNAB for years and it saves us loads of money and headaches on planning upcoming expenses.
Get any spare cash into the highest interest account you can. It will probably be similar or higher interest than your mortgage rate, so you're informally 'offsetting' your mortgage but the money is still there for emergencies/illness etc. Formal offset mortgages sadly still have stupidly high rates.
Pay for (phone/online-much better choice and more convenient) therapy for your DH and maybe have a free legal appointment to check that the money really is lost to you/him.
Electric throws and heated bed underblankets, good coats etc are great, but you can buy them nearer Winter if your money is saved, plus it will continue earning interest until you need to spend it.
Good luck, it sounds like a real eye of the needle situation, but things generally improve with time, as long as a you can both work as a team.