This is what I did, it may help.
I had a crisis with my mum and it was clear she could no longer live fully independently, and due to many years of neglect her house was uninhabitable, needing months of work to make it so.
I considered both sheltered and sheltered extra care housing and started looking in the area mum lived. I worked out that this would need myself or my brother to visit her at least once a month, and to go down for every medical etc appointment. The once a month bit I thought we could manage but the medical appts would have been too much for me. I wasn't sure how reliable my brother would be (he did do a vanishing act on other stuff) and it is a 7hour round trip for me and a 4 hour one for my brother. I realised that with a part time job and kids aged 8 and 12 and brothers then aged 6 and 4 it would be nigh on impossible, childcare constraints would leave a 6 week hole in the summer as well.
So I looked at accomodation for my mum near me. I started with sheltered, thinking I could set her up with local carers through friends and care agencies but realised that she wouldn't 'fit' in the 2 sheltered ones I looked at with dementia.
So I looked at the available sheltered extra care available in my area, a choice of 2 and one was a good fit and had available flats (shared ownership or outright sale as she didn't qualify financially for the rented in the same block). She started with carers twice a day to supervise her meds, and 5 and a half years later it has been the best choice although she has a lot more care visits now. Once she'd settled, she really liked it, thanked me for choosing it, said she did miss her friends but realised being near me was best.
I only knew at that stage what I had read on this forum about dementia, and it was made clear to me that if mum wandered or was aggressive or other difficult dementia behaviours I would have to move her (to a care home).
I couldn't have coped with supporting her in her own property locally to me, and small bungalows and flats are in high demand here, with the kids and job I didn't have the time to fully run 2 households (I do do her finances and shopping).
The 'best' decision needs to take into account both what you can do and what your mum needs. Her needs are only going to get more, and if it is a 5 hour round trip can you do that easily. It depends on if you have a job and dependent children.
If her house is suitable for now and she is self funded see how it goes for a bit - with whatever level of care you think she needs put in place.
You don't say how she is managing on her own without your dad, or what she can do on her own.
And don't forget you are grieving for your father as well.