What you've had to endure really sucks, and I'm very sorry that you're in the situation that your family are in. I can completely understand where you're coming from in relation to basically be living for your grandkids, and doubting your happiness in other ways. We've been through a lot in the past few years as well, I was forced to walk away from my job after 17 years and go on permanent disability in '15. We had to sell our home and live with our son and his family for 2 years. In 2020 my older sister went into the hospital for a month before she died due to a massive infection due to her RA medication that had destroyed her immune system. This was when covid had hit the fan, which meant that no one other than her husband was allowed to see her, not even her own kids could visit. So she went into the hospital, and a month later she was gone, we never saw her again. She was only 64.
I've been living with chronic pain due to osteoarthritis and neuropathy in my feet for 10 years now. My wife works full time to support us, but we're still screwed financially because of my retirement, my SSDI benefit is considerably less than what I was bringing home when I was still working. We'll never own a home again, and when our current lease expires, we have no idea where we'll end up living.
Depression and chronic pain together can have a massive affect on your out look in life, and right now I'm basically existing to see our grandkids grow up, that's it. We have 4 grandkids, our son has 2 daughters who are 17 and 13(holy crap), and our daughter has a boy and a girl ages 9 and 6. I'm trying to create as many memories as I can with them before I'm gone. Luckily they're all here locally, growing up my grandparents lived 1200 and 2000 miles away, so we rarely got to see them. Thing's aren't ever going to get better for me, I've accepted that.
Life isn't fair, and it never will be either.
Hang in there.