Can I let my dad claim my DTC tax credit and how should I answer to question about if this is a first time claim because I don't want to claim it for myself??

Yes, you might be able to transfer your disability tax credit to your dad, even if it’s your first year claiming the credit. However, to do so you must be dependent on him for some or all of the necessities of life (such as food, shelter, clothing) and a resident in Canada for at least part of the year.

This TurboTax FAQ has more information about who can claim a transferred disability amount: Is the Disability Tax Credit transferable from a dependant?

This TurboTax FAQ tells you how to claim the disability tax credit for yourself: How do I claim the disability tax credit?

This TurboTax FAQ tells you how to claim the disability tax credit from a dependant: How do I claim the Disability Tax Credit transferred from my dependant?

You may also be interested in looking at this TurboTax article on the Disability Tax Credit: Your Guide to the Disability Tax Credit 2022

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