Make it safe for her to declutter while retaining a sense of control.
Make the process as easy as possible:
- a place for everything
- lots of small wins
- clear and straightforward routes for getting things out
Multiple reasons for doing it:
- friend asking for clothes for local refugees
- local appeal for toys
One suggestion:
Hire a storage space with racking. Buy clear plastic boxes with lids which are big enough to hold a reasonable amount of stuff and small enough to manoeuvre, a non-permanent way of labelling them and some zipped bags for taking things away.
One full box at a time to the storage place. As the first item comes out, categorise it (e.g. baby clothes), name the first clear box "baby clothes", put the item in. If the next thing out belongs there too, it goes there. If it doesn't, the next clear box gets named ("wooden railway") and the item has a home.
If during this process things are found which can be let go, they get put into zipped bags and dropped off on the way home (laundrette, to be picked up and taken to the charity shop, dump etc). Nothing comes back to the house unless there is a space for it.
Rationale:
Items get put together which allows the person to see how much of one type of thing they have (Marie Kondo and all the house-tidying programmes do this). This makes it easier to let things go as you can choose the most important, and also have a sense of just how much there is in one category (rather than it just being 'stuff').
It will start slowly but get quicker and the result is much more likely to be permanent, not least because there is no feeling of being out of control.
It is largely one way - things will be going out of the house.
Notes:
Someone 'neutral' to support the process initially would be helpful - e.g. a professional declutterer or a really supportive friend - to get the process going with less emotion involved.