I would hesitate deleting a T5 from your tax return if the primary SIN is yours. I always split my parents' T5 slips but when I did, CRA asked why my Dad wasn't reporting the full amount in the T5s/T3s (although a 2 minute check into my Mum's same year return would show the combined full amount).
I haven't responded to the CRA and now my 93 year old Dad got re-assessed. Argh.
