You can only claim expenses that you incurred to earn your self-employment income. You can’t claim any personal expenses. So, you may be able to claim some of the expenses you help pay for, but only the ones that you directly use for your business. For example, if you pay your family’s phone bill, and you use the phone line 20% for your work, then you can claim 20% of the phone bill as an expense.
Also remember to save any receipts, bills, logs etc… that back up your claims, as the Canada Revenue Agency (CRA) may ask for them in the future.