Can I share my storage with only one family member without the others

Sorry, no. If you share an iCloud storage plan it is shared with everyone in your Family Sharing. Everyone who currently has a free 5GB plan is automatically added when you share; any that have their own upgraded storage plan will be given the option to join the shared plan or keep their own.

See the following from Share iCloud+ with your family - Apple Support

When you share iCloud+, any family members using the free 5GB plan are added to your family plan automatically.

If a family member is already paying for their own iCloud+ plan, they can choose to switch to your plan or keep their own and still remain part of the family. When they switch to the shared family plan, they get a refund for the remainder of their personal plan. They can't keep their current plan and use the shared family plan at the same time.