Firstly, I am very sorry about your brother. And I hope that you start feeling better as well. You are going through a rough time, so remember to be gentle with yourself.
I don't know a ton about the Canadian retirement system, just a bit from talking with my in-laws and researching some issues for them. I used this calculator to show my FIL what they might be able to expect from CCP and OAS when they retire:
https://www.canada.ca/en/services/benefits/publicpensions/cpp/retirement-income-calculator.html
You might want to go through it to see what you might be able to expect. You can run a few different scenarios, including retiring now or working part time and delaying retirement for several years, etc. You can add this to your anticipated payouts from your RRSP and other retirement savings to see what you might be able to expect as your monthly "income" in retirement.
The general wisdom is that you want to be able to replace 70% of your preretirement income with your retirement savings (including work pensions, government pensions and other savings vehicles) while only drawing down 3-4% of your savings per year. So someone who makes $100k per year preretirement would want to have enough savings that they would have $70k per year in retirement. This would come from all income sources, so your CCP, OAS, RRCP, etc. would all contribute towards that. The 70%/3-4% is more of a guideline than anything. Some people will be able to maintain their standard of living on much less. Others retire and find they their expenses actually increase, especially in the early years of retirement, because they choose to travel more or engage in more hobby activities.
And honestly, reaching that 70% number can be hard, especially for those who haven't been saving on a regular basis throughout their careers. My in-laws are a perfect example. They moved to Canada about 16 years ago. They won't have lived or worked their long enough to be eligible for full CCP and OAS benefits. They have saved very little into their personal retirement accounts over those 16 years and they still have a huge mortgage payment. My FIL is 60, my MIL is 52 and they no prospects of retiring any time soon because they just would not be able to afford it. DH and I worry a lot, which is why we are so focused on ensuring our own finances are in good order. We know that we might need to help support them later on and we want to be prepared for that reality.
And if your aren't keeping a careful eye on your monthly budget, then I would start doing that now. Knowing how much you are actually spending will be one of the best tools you will have to ensure that you can transition into retirement successfully without overextending yourself. Careful budgeting will let you know if you need to cut down on expenses in order to afford retirement and help you decide where those cuts should come from.