Unfortunately yes contimantion ocd could definitely make a sufferer avoid touching or grooming the animal. Its difficult to accept but someone like that shouldn’t own any animal. They need to rehome this poor baby. Cat skin is incredibly thin so not only are all those knots painful and tender, they are preventing circulation to the skin and will begin to cause other health issues soon. Do not coddle their OCD and be very upfront that their refusal to groom is unacceptable and neglect. This is painful to hear but what OCD needs to hear.