If you are already receiving a pension under the Québec Pension Plan and your spouse dies
You can receive concurrently a disability pension and a surviving spouse's pension. In such case, the Régie pays both pension s in a single monthly payment, called a "combined pension".
The amount of a combined pension is not necessarily the sum of the 2 pensions because it is subject to a total maximum amount set by law.
Note that...
As of age 65, if you receive the maximum amount payable for a retirement pension, based on your age when the pension began, your surviving spouse's pension may be reduced to zero.