Hi
@Mikesdaughter1971, welcome to the forum. I expect this is quite a step for your Mum and she will naturally feel quite nervous, but at the same time drained from looking after your Dad. Without knowing Dad's needs and condition (e.g. is he a wanderer?) it is difficult to advise on the type of care home required, but any good home should look to do an assessment of need. If your Dad has quite high needs some care homes, even with dementia dedicated facilities may not be able to meet those needs.
Do look at the CQC reports, but often these are quite out of date and are a snapshot in time, and the care home can change quite quickly with turnover in staff (particularly management) - which can sometimes be a positive (if a negative report) or negative (if a positive report). What I am saying is don't automatically rule out a home due to an adverse CQC report, as a lot depends on the reasons and what they have done to remedy the situation.
When you visit all areas of the home should be accessible, I found one provider wanted to speak to me away from the main areas which rang alarm bells for me. It is quite important to see how staff are interacting with residents (e.g. if there are lots of room assistance buzzers going and seemingly little action that might not be the best sign). One thing that helped me (to show to Mum later before she visited herself ) was to take pictures and video on my phone - you need permission to do that but it can help if you need to show you Dad or even to jog your own memories.
Again it depends on what Dad's needs are, but there should be a weekly schedule of activities for residents, I would expect them to explain that to you, along with the basic amenities like food menus, hairdressing, how they deal with medical appointments, medication etc.
Other things like the room facilities you will be able to evaluate, visiting a few will give you a better idea. The main advice I would give is trust your own instincts. Any other questions just ask. Keep posting.