also, i might sound a bit heartless here, but what does she have savings for if not to use for either unexpected spendings or saving up to use when she needs to?
How long has she had the flat? What has been happening to money she has paid for maintenance? has it all been used or is there a pot of money that can offset some of this work?
Does she have the abiity to reject all three estmates and not have the work done? What do the other neighbours think, are they just all paying up?