Hi Adamc
This must be incredibly hard, watching your dad experience such frustration while not appearing to do much about it. Such an experience, as an observer, can definitely be triggering in a number of ways.
As a 51yo gal who's lost some ability, based on the natural aging process, there are times where I find a sense of loss a little challenging. It can actually threaten to be a bit depressing at times. And as someone who's watching 2 aging parents go through ongoing loss, due to the aging process and ill health, what I tend to witness is my parents feeling sorrow for themself. Instead of 'Feeling sorry for our self' I've found it's much healthier to address feeling sorrow and why we're feeling such sorrow.
To lose that sense of self who could effortlessly mow the lawn or whip the edges at some point might be a challenge for your dad. To lose that sense of self that had a brilliant memory at one point could also be challenging. To lose that sense of self that could easily find the best in a bad situation can be a massive challenge. The internal dialogue that can come with all this can point to having gained a sense of self that can be highly triggering - the inner critic. The inner critic can sound a little like 'You're useless, what good are you to anyone?!' or 'What's the point in being here when you can't do much anymore?!'. They're question/statements, combined. It's the type of dialogue that can offer a constructive question while stating a depressing observation. This leads me to wonder whether your dad might be struggling with depression to some degree.
I've found that the most important factor that comes with a sense of loss or a lost sense of self is...it must be replaced with a constructive one. If not replaced, a depressing void remains. While you offer cordless tools to replace corded ones, which is a naturally brilliant solution, maybe all your dad can see is the sense of self he's lost that could once work with corded tools.
While at 84 my mum is open to self development, at 87 my dad's not. He suffers through not budging. My mum works on gaining a new sense of self just about anytime she loses an old one. While once being an incredibly fit woman, she now works on developing a sense of self that enjoys being pushed around in a wheelchair. It's a massive challenge for her, to change the way she identifies herself, but she's getting there. As I say to her 'To develop the skill of manipulating your own brain/perception can pay off'.
