He is experiencing difficulties with correct letter and numeral direction of formation. Banish yellow pencils and cheap ballpoints totally from your room or home. Start with unlined if necessary, then lined later.
Size can shrink once control and form are established.
Use a gold liquid marker to make a small dot where the letter starts, and small arows for direction. Put the letters on large file cards in a box or sheets of posterboard in a large binder. Have the student trace the tactile letter using the dots and arrows as guides. At first, hold his hand and guide it if necessary. Say the directions and trace the letter over and over.