Hi Anu001 - I’m sorry that you have been suffering with an inherited condition and that your father hasn’t been terribly helpful (to put it mildly). This must be very painful for you in so many ways.
You are absolutely correct that your provincial income assistance, PWD, and the Canada Revenue Agency are really quite separate. Your PWD designation and payments just started in 2018. This PWD is not a CRA designation and is NOT retroactive to any period where you happened to live under the same roof with your father.
If you decide to apply for the Disability Tax Credit at some future point, this non-refundable tax credit can be approved retroactively for up to 10 years. You are not obligated to inform your father about your approval for the DTC. You are an adult. Your father is NOT entitled to know anything about your financial affairs. For your father to use any part of your DTC for a previous year, YOU would have to agree you were dependent on him and YOU would need to sign a form allowing him to use any part of the DTC you couldn’t use for the purpose of receiving an income tax refund for a previous year. You see - It’s all in your hands… except that you must apply for the DTC and you need to be approved. As Elaine said, there are lots of incredible benefits TO YOU of being approved for the DTC (grants, bond).
The “taxable income” level depends quite a bit on the province where you live and the amount of income, type of income, deductions and tax credits you may have. I’m not sure which provinces use the Persons With Disabilities designation, PWD, designation outside of British Columbia. If your only income is PWD income, basically income assistance, you are in a very low income bracket and won’t be at a taxable income level. Since you know quite a bit about PWD and CRA, you are already well informed or have received good advice from your case worker or another professional.
Be confident and please focus on your wellness and not on bad vibes from family members or anyone else. If you are in BC, Disability Alliance BC (a non-profit organization) may be able to help you with your Income Tax this year. They have some excellent website information on lots of topics, including the Disability Tax Credit. If you live in BC, Disability Alliance BC will work with you, at no charge, to prepare your DTC application and some information to help your doctor complete the form.
Best wishes to you.