Will I regret this?

It sounds like everyone has the best of intentions but I'd be wary. My friend did this in similar circumstances to what you describe and it ultimately cost her her marriage despite her husband being fully on board at the start.

Don't underestimate losing your own home as just yours, she found she had no way to switch off.

A work colleague did this,we were both nursing,she had an identical house to mine,but they demolished the utility room,to make a sitting room for her mother. She said it drove her nuts,and only consider it with completely separate accommodation and front door. My lovely DM was my best friend,she came to live with us post operations and it wasn't easy

Please read the cockroach cafe threads and especially posts by @ithinkisawahairbrushbackthere several posters have done this, others have cared for elderlies for many years as daughters round the corners. We have all been massively affected by this . I have been carin* for up th3 road dm for 16 years at great cost to me and my health. However lovely the elderlies are or were.
get legal/ financial advice from age uk.

Does your sibling have a view on this? Will s/he have any input in their day to day lives?

You sound like a very kind caring person with a great DH and immediate family, but I would bear in mind that most if not all the caring, waking in the night, washing, cleaning, doctor's appointments etc. will fall on you. I know you say you will get care supports, but things are OK at the moment. Think about down the road a bit, and work all the scenarios through.

There are many on this board who will offer their tuppenceworth and their experiences. Wishing you the best.

I could never ever do this and tbh, I don't think much of parents that would allow their busy adult DC in the prime of their lives with jobs and families of their own to make such sacrifices indefinitely. As lovely as relations may be.
I want my DC to live their own lives and be free of ties and 'challenges' and if that means buying in care or going into care then reluctantly, so be it. Its what we save for all our lives isn't it? To ensure we are are and cared for in old age. Anything else is highly selfish and unfair.
Their happiness and wants do not take priority. And as an ex district nurse of many years I've seen similar set ups cause massive stresses down the line. Usually for the women involved. My own DM ended up on antidepressants and BP medication doing similar.
Good luck whatever you decide.

I think this is great. If I was single I'd do it in a heartbeat for my parents. My issue is my OH who is quite different from my family and the way we were brought up, and basically I don't think it would be a compatible situation for us at all. (which I'm really sad about but I have to be realistic). So I think if your husband is on board, gets on well with them and has even suggested it, then I'd 100% go for it in your shoes. They won't be around forever, so enjoy what you can, and bring what joy and support you can to them too.

I know you are asking about the emotional side but I would be a bit concerned about some of the practicalities. Firstly your mum might be fine with a stairlift but if she turns out to have Alzheimer's this may not work for very long. Secondly I am not sure tgis wouldbe the best thing for your dad, if he gives up his home, I think you need to wait for the memory clinic to find out your mum's prognosis sadly with Alzheimer's it can be only a couple of years and ten he is lonterm living with you (savings maybe used up incare fees)and this might not be the best thing for him.

That's a lovely thing to offer to do. Your parents are very lucky to have you.

Your parents will still need a lot of care, and it is very possible your mum will be best cared for in a nursing home where she can have 2/7 care as her dementia progresses. So do make sure they protect their money and spend it on their care so you all have a good quality of life.

If you and they both want to do this then go for it, but I would try to make sure that there is an additional care package in place too because you and your Dad will almost certainly need the support as things progress.

If your parents could help fund it then maybe some professional carers could come in two or three times a day? It would help keep things as manageable as possible for you and your Dad. Otherwise, it could get very tricky and draining.

It’s impossible for a stranger to give you meaningful advice on this. I love my parents and we have plenty of space but I know I could never have them live with me. They are lovely people but they can be very annoying and I couldn’t deal with it day in and day out. I’m also just someone who really craves private time and space. I couldn’t imagine never being with just my DH and kids. Grandparents are family but the dynamic is different when it’s just the four of us, or the two of us after the kids go to bed. But I know not everyone feels the same way and everyone has different family dynamics.

You can have them there and use their money to pay for care so you manage them rather than having to care for them . Can you give them their own front door in the garage so they are self contained ..
rules need to be in place and boundaries before you start though .