Do senators families get senator's retirement after his/her death?

I will assume you are referring to United States senators for the purposes of this answer.

Here is what happens when a senator passes away while in office:

Employees in the personal office of a deceased sitting Senator are continued on the Senate payroll at their respective salaries for up to 60 days after the Senator’s death, unless the Senator’s term of office expires sooner.The Committee on Rules and Administration may extend this period in cases where it will take longer to close a deceased Senator’s office. Employee duties are performed under the direction of the Secretary of the Senate.An amount equal to one-tenth of the official office expense account portion of the Senator’s Official Personnel and Office Expense Account is available to the Secretary of the Senate to defray those expenses directly related to closing a Senator’s office. Expenses are paid from the Contingent Fund of the Senate as Miscellaneous Items. The Senate Financial Clerk provides information concerning allowances for the operation of the deceased Senator’s office during the 60-day period.
A deceased Senator is removed from the Senate payroll as of the date of death. The Employee Benefits Section of the Senate Disbursing Office ascertains any benefits due to a beneficiary previously identified by the Senator, or the widow or widower or other relevant survivors. The Senate Handbook indicates that “[i]n the next Appropriation Bill, an item will be inserted for a gratuity to be paid to the widow(er) or other next-of-kin, in the amount of one year’s compensation.” By statute, a death gratuity is considered a gift.

Source: https://fas.org/sgp/crs/misc/RL34347.pdf

Concerning a pension after death: A survivor annuity payment commences that is separate from the pension that the senator received.

Source: http://www.gao.gov/assets/230/221239.pdf