Can the will overturn the agreement?

In fact, the agreement can also be regarded as a will, but the house is disposed of and signed by your parents, which is legal and valid.

However, your mother later made a will, which can overturn the previous will.

Specific to the case:

1. The protocol is valid. When your father dies, you inherit 50% of the ownership of the house enjoyed by your father according to the agreement;

2. Your mother's later will overthrew the right to dispose of 50% of the ownership of the house that your mother enjoyed in the agreement, and it was executed according to the final will (shared equally by four people);

3. To sum up, you should get 62.5% share of this house, and the other three people each get 12.5%.