I agree leatherique system will work. I fixed some seats in similar condition.
I sent a swatch of the leather in to leatherique and they matched the color. Actually many models they have the color in stock.
I first applied the leatherique oil system about 3 times. Each time, I hand-rubbed the oil in and then immediately covered the seat with a black garbage bag. I then left it out in the sun to "bake" all day. I then cleaned with Prestine clean. Multiple treatments are necessary to clean and soften the leathe for drying.
I then used nail clippers to clip off any leather "hangnails."
You may find that after multiple oil applications, the cracks are not as visible and will not require filling with crack filler. You might just be able to re-dye. Your photo looks like re-dying alone might be enough.
If you do need crack filler, leatherique has this as well.
I filled the cracks on my car with a small amount of the leatherique crack filler. I used a flat artist's palette tool (it's like a very small spatula but with smooth (not-sharp) edges. I did not sand. I used the flat of the tool to spread the filler into the crack and the edge to remove excess from undamaged leather.
I am afraid of the sandpaper and did not use it. Try just using the clippers to removing hangnails if any and then spread the crack filler carefully and evenly.
If the crack is deep, you can "build up" crack filler with multiple coats, but the photo does not look too deep.
Here is an important tip for dyeing. Before dyeing, apply the pink prepping agent and wait at least one day for it to dry. Otherwise the dye will not take well.
After drying, do not immediately clean with the Prestine cleaner (even though the leatherique instructions say to do so). Wait another day and then clean lightly. Otherwise the dye will rub off.
Repeat the oil treatment after dyeing for best results.
Now the bad news: If the crack is in a high-use part, then the crack filler will eventually "pop out." But with care it should look good for at least a year, and re-appying will be easy because you just have to re-apply crack filler and re-dye the crack filler.
Good luck.