You would need to contact our deceased estates team to see what is included in her estate upon death. In general however, the sale of a property will be subject to Capital Gains Tax.
However, if this was the main property for an indivudal, they will be entitled to private residence relief for the period of time lived in.
Please see here for further guidance which also outlines rules for when someone goes into a care home, under the section for period of ownership.
Private Residence Relief (Self Assessment helpsheet HS283)