Here's some information on being a beneficiary:
Inheritances themselves (i.e. assets at time of death) are generally
not taxable in Canada, but any income earned by the estate is.
Beneficiaries have to report income distributed to them, which are
generally reported by the estate on a T3 (Statement of Trust Income Allocations and Designations).
Income you earn as an executor or trustee is taxable and must be reported.
http://www.cra-arc.gc.ca/tx/ndvdls/tpcs/ncm-tx/rtrn/cmpltng/rprtng-ncm/lns101-170/130/dth-eng.html