At this stage I would get the preschool books at the dollar store to draw large circles, squares, lines etc. If he can only sit for a couple of minutes have him draw one line, and gradually add more as he is able to sit longer. Sit beside him at the table, push his chair in so that he can/t easily climb out. Let him pick the colour of marker that he likes. Make sure to reward him after he has made his mark. Combine this with praise for sitting and writing. Have him put his line one the fridge so that everyone can see what a good job he did.

Hi, There’s a good workshop on ConnectABILITY on this topic. Go to https://connectability.ca/2010/09/25/family-literacy-2/ I would also suggest having the school put in a referral for a consultation with an Occupational Therapist. The OT will be able to make suggestions on how to improve his fine motor skills and attention span. Often children have difficulty staying seated. The OT will also make suggestions around what you can do to help him stay seated longer.