NP mate, I symptahise. I'm in the same boat with our youngest and it is worrying but I try to be as positive as I can.
Sadly there are always people who lose out through no fault of their own and yes, tragically, some just can't take it. My elderly parents have lost almost all of their meagre investment income following downsizing and the remaining capital won't last long. My Dad cares for my mum and they survive on CA and a tiny state pension (£85 pw?) because he was self employed all his working life.
If I look into the future when I can no longer care for my lad I start to get very depressed but then I just think about all the kids around the world who're starving and dying and have never had the quality of life he's had. It's all relative isn't it.