I can sympathize, I have a spot on my right abdomen that itches like crazy when I put adhesive on it. I mean it is terribly annoying, but I am an adult and I put up with it. I wonder if his skin itches all the time, or just in certain areas? I rotate my spots so this site ( it is in right now) that itches, only is used three days out of every 12. That does help me. If it is in one spot look for other sites, of course that may or may not help.
My other advice is to look at other adhesives. I know MM has different sets, with various degrees of glue on them. I also know that I will often use a non glue cleaning pad, in this one area. Lots of people use IV 3000 bandages. I cannot use these, Instead I use Reliamed bandages. They stick a little better and are less irritating to my skin. I use these with the pump site, for reinforcement and with my CGM site. Here is a site to look at for the bandages I use.
I also use the reliable protective barrier wipes, this seems to cut down on the amount of itch. here is this site.
I cannot swear by this, but a buddy of mine says he uses this natural spray to combat itch. I am not a user, so i cannot swear to it, but it may be worth a try?
Finally the best sop to use is cetaphil. This has been a life savor for me and I use it every day all over. I realize you are asking about a specific area but i use this soap all over and it helps a lot. I also use Cerve’ cream, not lotions. Lotion is a water based program and needs to be avoided.
Good luck, This is miserable