Hi there,
Fantastic that you're considering further education when you have so much going on at home. You sound very motivated, ambitious and sensible for considering the practicalities before fully committing yourself.
Volunteering - most hospitals would love to have you. My local hospitals are forever advertising for volunteers to come in visit people in the wards. This could be for helping them along with their communication if they'd had a stroke or even just for socialising if they don't get many visitors.
You could contact a specific acute team at the hospital such as SALT, OT, Physio adult services and ask to come and shadow them for a few hours to see what they do with the patients.
As for childcare - you will need to find reliable school holiday cover for when you are working in a healthcare role and for any resit exams you may have to take or summer placements etc (e.g. when I was training, if you failed a placement during the year, you'd need to redo it in summer).
My daughter goes to a childcare setting that has many children with additional needs and they receive outstanding care throughout the day. This is not a specialist setting. It might be worth touring around different settings and finding a nice, smallish childcare facility. My 11yo goes to a nursery that also has some out of school care spaces. It's wonderful.
In terms of affording childcare, the college should have a childcare fund or discretionary fund available that will pay most - if not all - of the childcare costs for the year and you reapply each year.
Basically, you'll not be able to do the course or accept a job after it without childcare in place.
Getting appropriate childcare set up sounds like it will be very difficult but certainly achievable if you research and visit every facility (childminders, nurseries, out of school cares, consider a nanny) that is accessible to you.
Good luck!
If using registered childcare is definitely not an option you'd like to consider for whatever reason, you might consider doing a distance learning course instead so that you're still building up your skills and training while being at home with the kids if you envisage returning to work in the future.
However, be aware that many distant learning courses (particularly those related to health and social care) require you to attend at least one lecture at the campus through the year and attend placements.