Pain definitely comes with MS, it was one of my earliest pre-diagnosis symptoms.
I take a lowish dose of Amitriptyline (Elavil) at night for it, works really well. Both Neurontin and Amitriptyline can be sedating but it varies from person to person. For me the benefit of sleeping at night far outweighed being a bit sluggish in the morning.
Hope that helps and hope your Dad can eliminate at least the pain from his MS equation.
RR-MS dx 1998 and Coeliac dx 2003
Tecfidera, Cymbalta, Baclofen.
EPO, Fish Oils, Vitamin D3 2000 IU, Magnesium, Multivitamin/mineral, Co-Enzyme Q10, Probiotics, Milk Thistle, Melatonin.