I was told that neuropathies can also be caused by long standing spinal compression. I suffer from Cauda equina Syndrome which was not diagnosed for seven months and am left with bilateral drop foot, in addition to Bowel, Bladder and sexual dysfunction. I had a mri of the brain to rule out MS and stroke and was left with the impression it was the long standing compression that left with drop feet.
The term neuropathy usually refers to a problem with the peripheral nerve (that is, the nerves that travel from the spinal cord to the muscles/skin)
Neuropathies can occur in stroke patients due to compression of a peripheral nerve in the arm and leg due to recumbency of that limb from paralysis
However, it seems form your description that the numbness was caused by the actual stroke itself (the back of the brain involved could contain the parietal lobe which controls sensation). As the brain heals/recovers from the stroke, the pattern of sensory loss may change somewhat, and may fluctuate. It is still possible that more brain area has become involved in the stroke, that is, a completion of the stroke in that arterial territory. Your doctors may need to correlate these findings with the brain scan to judge the extent of the stroke
There are also some more specialized brain areas which can result in more widespread sensory disfunction (such as the thalamus or the secondary sensory area), even a small stroke in these areas can cause more widespread dysfunction. I'm not sure if this is possible in your fathers case.
Either way, one cannot predict the course, if there is no ongoing or recurrent stroke, a slow recovery will occur over time and can be best judged at 3-6 months after the stroke. Symptomatic treatment of the sensory symptoms may be attempted with medications for nerve related pain like neurontin, but cna be difficult, and may need reccomendations from a pain or rehab specialist