I have had great success with silicon gel sheets made for scars. They use them to line burn victims pressure garments etc. You wear the gel sheet over the scar as much as you can every day, wash in soap and water and then re-use. Each sheet lasts a month.

Product names include Scar away, Smith and Nephew Cica care gel sheet.

For his leg I would put a sock or wrap a crepe bandage over it and wear it at night. It's really working well on my surgical scar- even better than Mederma.