What are you going to talk to her about? How will you broach this? I'd tread very carefully.
One of my good friends fell into hard times some years ago. She'd come to my place (at the time, it was just me and baby DS - so easy for me to keep everything tidy and clean) and would often say how she felt muchbetter coming to my place, as it was peaceful/neat/tidy. When I went to hers (hadn't been there in a long while as we'd meet at mine or out and about), it WAS messy (and really dirty), there were piles of dirty laundry and rubbish everywhere, unwashed dishes everywhere etc, washer machine not working, stuff not clean etc....but it was because she wasn't in a great place herself, and she just didn't know where to start with it all. She told me about all this, so I just offered to help her get things back on track. She was happy to accept the help. I certainly didn't judge her, I just felt awful that she'd not said anything before.
It took 5 days, but I scrubbed her place down (including oven/cooker/fridge and freezer), helped her to declutter/tidy the place, washed up everything, worked out how to fix her washer machine (and fixed it), and then between us both, got all her (and her 2 DC's) laundry washed, dried and sorted. I did a food shop for her, restocked her kitchen and batch cooked some bits. She was stuck in a rut, was just out of a difficult relationship and it was a nasty catch-22 situation for her. She couldn't see where to start, couldn't face doing much as everything had overwhelmed her...so nothing done, and place carried on being a mess. Same thing could have easily happened to me.
If she hadn't said anything, and was in a good place/fine with how her house was, there's no way I would have said anything about helping her clean the place up. After all, it's her house and it's not for me to say how she ought to keep her house. It was only because of her being upset at her situation and actually telling me about, that made me offer to help her.