Wow, thank you to everyone who has responded. I usually have a sense of what the best thing to do is, and it is totally absent in this case so I am just continually second guessing myself. I've also realised that they are looking to me to decide what is best much more than I had realised so I have to be somewhat careful in what I suggest.
I can afford to give the 'loan' out of my own savings, it isn't a problem for me (a small problem for my partner, but manageable!). Their current income from pensions is around €3.6k per month.
Prior to this property becoming available (and we just went sale agreed today, including paying a booking deposit), I had already arranged for them to take a 12 month lease on an apartment in the same building as the one they loved. I wanted them to stop being in a position of desperation where they were lurching from one property to the next and the continuous crises. They are supposed to move in tomorrow and sign the lease. The lease of course, states that if they break the lease before the end of the lease term, they both lose their deposit and are liable for any rent until it is let to a different tenant.
The property they have gone sale agreed on is a small house, thus the stairs. The price is 560k. They do love the space of it - as a house, it has 30% more space than the biggest apartment they looked at as well as a private back garden and own entrance. It is in very good, turnkey condition.
I feel like we are committing to two contradictory paths at the same time - signing a lease and going sale agreed on a house at the same time (with the expectation that we can close on the house by Christmas), and I don't know which is better.
We could take the 12 months rent and keep an eye out for something which is 'perfect', yet perfection has not been found in a year of searching. They are in their 80s. There is a pandemic happening, they want to be somewhere and be able to unpack all of their stuff which is currently in storage. The apartment is fully furnished so they would not have the opportunity of unpacking there.
How long can they put their lives on hold? Should they just take something now that is imperfect but their new lives in Dun Laoghaire can actually start? They don't want to consider anywhere else - they want to be somewhere they can walk to anything they could ever want as I have forbidden them from driving again - for good reason.
Yes, the 7 figure sum for repairs would be split across all units, the cost to their unit would likely be in the region of €70-90k.