It depends on what housing agreement they have when KW added his name in.
There's 2 types:
Type 1 - share of the house is 50-50, regardless of how much each person contributed.
Type 2 - share of house is calculated based on how much each person contributed.
If it's type 1, then the proceeds of sale will be split 50-50. The amt KW receive will first be used to return to his CPF, INCLUDING ACCRUED INTEREST. Which means whatever interest he was suppose to earn if his CPF $$ still inside his CPF, needs to be returned upon the sale of the house.
If it's type 2, the same thing will happen with the CPF $$.
If there's extra cash after settling the CPF thingy, then it's up to them how they wanna split the cash. But if there's a dispute on the cash portion, then HDB will split it according to the type of ownership of the house.
Currently there's alot of subsidies. My friend's got 50k subsidy (cos her basic pay very low, hers is allowance based so due to 'low income', they got higher subsidy).