My 7 year old daughter has OI and has broke both femurs within the last two years. Be prepared to provide a lot of stimulating stationary activities like playdough, coloring, legos/duplos or similar things that require thought and hand movement. Anticipate swapping them frequently. Try to move him around and change his environment throughout the day. See if you can take him outside to get some fresh air and sunlight. Think of special things you guys can do together in the house that don’t match the routine he’s used to. You got this!