Hi, My Housbend In 40 Years Old He Have A

Hi,
my housbend in 40 years old he have a problem with left hand numbness this issue start from 2 months ago he had a mri and spinal test it shown 2 white matter in his brain but the result of spinal test was clear, his Dr doesnt have any suggestion to that i dont know what kind of diseas would he have ,i noticed his memory was change from a couple of monthes ago i am so worry about MS could you please help me to find it.
thanks
simin