Because you want to help her, I'm happy to comment, sorry about the length!
I have hoarding disorder, grew up in a squalor hoard, and have worked with others with HD. It's possible to help someone who wants and is ready for help, but it will always be on their terms because it is their MH causing issues, and self aware or otherwise, most instinctively protect their MH from further damage.
The thing to understand most, is that 'the stuff' and the 'relationship to the stuff' is the symptom of an underlying MH condition, not the actual condition. It is that symptom that people (both with HD and those around them) find distressing and troubling, not their condition. So trying to remove the symptom without dealing with the condition, always hits trouble.
The body and mind puts out symptoms for a reason. They are there to demand you pay attention to what you have going on that isn't so obvious.
Anorexia is a good example. The symptoms are awful and will kill if untreated, but the symptoms aren't actually the cause. Forced feeding isn't a cure.
I grew up in a squalor hoard and it's unsurprising that the presentation of my own HD (I thought I'd escaped, but no) is an opposing sub group: highly organized, tidy, and at one time obsessively OTT clean. (some might argue I still am, but now days I'm much closer to 'normal standards' than I ever have been)
People often don't recognize the presentation as hoarding because the symptoms doesn't yet impact on others lives.
Despite what those making money from it claim, hoarding as a disorder isn't really how much stuff, how it's kept, where it's kept, or what it looks like.
It's properly defined by how extreme the difficulty and distress is caused to the individual when attempting to part with an excess of possessions if they need or want to.
Some situations look like hoarding and aren't, others look they aren't, but are.
People say you can't organize and clean clutter, but I have gone into several hoarded homes (including severe) and done exactly that. When you go in with a 'nothing leaves unless you ask me to remove it' attitude, you will have far more success (including things leaving voluntarily.)
Being trustworthy is huge. Many people with HD have suffered abuse and or huge losses and have learned trusting others is a dangerous painful path.
There's no magic wand with "report, log it, SS, Fire brigade." It's an MN chicken myth! If there was, all the desperate self aware hoarders, just wouldn't exist.
IME the better end of SS will try and make her pay them for someone to come and clear/clean and if she has no funds but owns, put a lien on her home.
It isn't a route I'd advise as it usually results in the person severing arrangements and becoming introverted and less trusting. It rarely ends well.
Talk to your local FB. Some are brilliant and sensitive and really helpful, others can cause more harm than good. All will come out and put basic alarms in, not all will respect her home and property while doing it sadly, and this can backfire. All will put a flag on her address if they feel it is severe. Most have a protocol they will follow regarding SS. If she is a home owner and of sound mind, she can refuse any and all of it. If she doesn't own she has less rights.
Actual hoarders will take note of reassessing planning escaping fire, and prevention, but rarely will get rid of stuff to facilitate it IME. People do it when there is something they value more. It is rarely their own safety or lives.
She's asking for help, and you're up for helping. She's recognized a link between her need to keep 'stuff' and poor family relationships. That's excellent!
You can't cure her, and shouldn't try to, but she may have figured out enough to be ready for change. But probably only so much.
She's keeping 'a perfectly good kettle' as a spare. Perfectly logical when you have a fixed dwindling income and CoL all around. The question is how many of what are being kept? Are they all things that are likely to eventually see use? Are they deteriorating waiting to be used? What condition are they in, and have modern equivalents improved or gone downhill? (Ie: new irons are better, but high powered Miele vacuums now irreplaceable)
Updating her knowledge while acknowledging her better choices (even if accidental) is healthy.
Sometimes people superficially justify ie 'it's a spare' and discover when they try to get rid off that really it's a 'it represents X' bond. Until those things are unpicked people are likely to get defensive/irritated including with themselves.
She knows she has too much, but hasn't placed a literal value on space, or being able to move around easily. She may discover that sudden space doesn't make her comfortable, so don't go to fast. Adjustment takes time.
Very often people are clinging to the younger more vital, defined by work/parenthood/relationships self. So you'll find wardrobes packed with business suits, evening wear and heels, with no chance to use them again. Letting go means coming to terms with a diminishing future.
If you want to help her, go for it, but gently, and keep your boundaries in place.
You are doing (potentially) a nice and decent thing. You aren't responsible for it's success or failure, or her. Go into it reminding yourself of that. Organizing clutter always makes more mess initially. Always leave things in a way that doesn't leave it worse, then whatever happens you can always withdraw, temporally or permanently.
Sympathy and empathy go a long old way. No one wakes up thinking wouldn't it be lovely to develop a hoarding problem? Many hate themselves for it.
Gently understanding what the other persons understanding of rubbish, not rubbish but unneeded, and what they want to keep and why, is a good starting point. Accept there may be big gaps between theory and reality. Keep things light, and if appropriate, humorous.
Reduce danger. (including for you) Look at trailing wires, overloaded plug boards plugged into overloaded sockets, items too close to cookers etc.
Vacuum bags have their uses but usually eventually re-inflate, so bear in mind that you may be creating future chests of drawers that wont open etc. If you put them in boxes, don't put them at the bottom, re-inflation causes the boxes on top of them to be unstable/fall etc.
If you are going to box stuff, use identical boxes wherever possible, tape them with parcel tape, (not folding flaps into each other) and leave gaps between them and walls, and stacks for good ventilation. Keep weight very low. Stacks collapse and are dangerous to older people, make sure what could fall is light enough. Damp or failure to heat can make this happen faster than most expect.
Have her invest in see through sacks and bag the contents, prior to boxing. It massively reduces the potential for infestation.
Put like with like, and label on two top corners. If it's too much to put whole contents on both labels, put an arrow on the second one pointing to where the info is. Always put the label at the top of the box in the same place. It automatically says which way up the box is. (when boxes get taken on and off stacks and put back the wrong way round this stuff makes a lot of difference)
Generally I try and keep things in the 'correct' room, but sometimes that's not possible. But if someone can see they have 18 boxes of crockery, cutlery, and kitchen implements, in their kitchen rather than it being distributed over the house, then the idea they may have more than they need for a lifetime, starts to be easier to see, acknowledge and address.
Space can cause liminal discomfort to those used to being surrounded. What looks like great progress to you can be viewed very differently by others.
Focus them on organization and cleaning gains, and if needed place boxes into spaces and move them back gradually.
Personally I color code and stick a chart by the light switch as a place less likely to get covered. (ie Dark blue - clothes, mid blue - bedding, light blue - curtains)
I'm a little excessive over organization, but have learnt that what is excessive in someone like me, is highly useful to a chaotic hoarder trying to get a hold on their situation.
Your ability to access dumps, additional rubbish, recycling, charities/ shops, check values, and physically do things is incredibly valuable to someone without it. But familiarity can breed contempt. Nip in the bud if needed.
If the place is dusty wear a mask or tie a scarf at least, you don't want it all in your lungs. Shut the door afterwards, neither does she. Personally I wear gloves. Too many surprises lurk for me not too. If it's really serious especially regarding mold, fridges, disposal of dead critters etc use proper protective gear and filtered masks. Your health matters too.
Good luck to you both, what ever level you choose to assist her.