I've done some rough calculations. An imaginary tanker has two cylindrical tanks (100 m length, 10 m diameter) with 15700 m³ of LOX at 60 K. The payload is released 10 minutes before the expected collision and the tanker pushes off into a safer orbit.

Ten minutes later the gas cloud expanding at 220 m/s in each directions now occupies a sphere with a radius of 132 km (tidal effects omitted). It now occupies a volume of 7.3e10 m³ and has a density of 246 mg/m³, roughly the density of air at 60 km AGL. Since both the debris and gas clouds are going against each other at LEO speeds the braking effect would be equivalent to passing through the upper atmosphere at about 15 km/s.

Dynamic pressure would be somewhere around 25 kPa. A 1 kg steel ball bearing (something you

*seriously* don't want to see in LEO going against you) would be decelerated at a rate of around 75 m/s². It would pass through the cloud in roughly 20 seconds and lost about 1.5 km/s of its prograde velocity (more than enough to bring it down) and (guessing) a significant amount of its mass.

So, is it even remotely plausible or is it just weapon grade bupkis?