Estate Claims for Provision/Further Provision
The threshold position is freedom of testamentary distribution. That is the will maker has the right to choose the beneficiaries of his/her estate.
Legislation - Part IV Administration and Probate Act
The Court has jurisdiction to order that provision or further provision be made out of the estate of a deceased person for the proper maintenance and support of a person for whom the deceased "had responsibility to make provision". The legislation lists a number of factors the court must take into account in determining whether provision or further provision should be made to an applicant.
If the court determines that an applicant should have received provision or further provision from the deceased it will attempt to make such provision out of the estate as would have been made by a wise and just, rather than a fond and foolish, testator.
Depending on the size of the estate the court will attempt to provide a successful claimant to ensure reasonable accommodation (and if possible to purchase a house) and to provide an amount to leave the applicant with a fund as a measure of security for future expenses and contingencies.
The estate will often end up paying its own costs and, in many cases, a substantial proportion or all of the claimant's costs. This can often provide a powerful incentive to resolve claims made against an estate.