Usually, hair that breaks more than other areas tends to not be finer. It tends to be coarser. It's the coarser hair that needs the extra love and pampering. It doesn't hate you. You have to learn to better understand it. It's trying to communicate with you. So, you have to listen without judgement. Once you understand, it will respond to your love and attention with beauty and health.
Chicoro has a point here. I have an area to the right of my head that is far more coarse than the rest of my hair. I range from 3c - 4a, but this area may be 4b, or is simply just dry. Wash day was yesterday and it took me a significantly longer time to detangle this side. I used to try to detangle it at the same speed of the rest of my hair, but the frazzled ends are evidence that this was not the way to go. It was a lengthy process of very slowly working through the hair, stopping if any tangling happened, using my fingers to prevent knots, etc. Took forever, but the hair has been given what it needs to stop breaking.
Second, my front of hair area suffers and my bangs have trouble growing back due to heat and mechanical damage. Unknowingly, when I would straighten my hair, the frontmost part of my hair would be the part with leftover product (like deep conditioner, and it only takes a tiny bit to start cooking) or that I would go over more times to get the 'look' I wanted. It's been the shortest part of my hair for as long as I can remember, but the things I did to it were so in my subconcious that I didn't pay any attention to it. Mechnical damage was wearing buns - I would use my BBB to sweep that part into the bun every day when I bunned. This can and will cause damage! A lot of people aren't aware that brushing the hair /smoothing it out the same way frequently can cause mechanical damage, especially when it is wet and something like a hard bristle brush is used. I've hence stopped using the BBB on that section, instead I twist it and pin it back with a bobby and it creates a rather elegant looking bun.
All that to say is, it may sound silly, but yes you do have to take a step back, go through your motions and really pay attention to what it is you're doing with your hair to figure out these 'mysteries'.