My step dad has been having numbness on his hand , its been going on about a week .. can it be something to worry about ?

Check with doctor: Possibilities include thyroid disease, Vitamin B12 deficiency, diabetes, cervical spinal stenosis. He would need evaluation by a dictor, including bloodwork

Yes: nerves are involved when numbness is there. Can be at the level of the wrist, carpal tunnel, at the area of the elbow, the shoulder, or neck ( such as a disc injury) even at the level of the brain such as a small stroke or ms or tumor etc. He needs an exam and some tests so that it doesnt stay or get worse if possible to avaoid