Where agreement is not possible, the usual first step is mediation between the siblings, often facilitated by the estate's lawyer, to work out either a sale with proceeds split according to the will or one sibling buying out the others' share for their percentage of the value.
If mediation fails, a co-owner can apply to the Court of King's Bench for an order to force a sale, known as a partition action, though legal fees on that route often exceed the $800 to $1,500 a routine sale would cost and take considerably longer.
Most disagreements resolve well before it gets to court once everyone understands what the home would actually sell for. Get your hand-reviewed valuation from Joel Dyck.