Sometimes the team really needs the kid, and sometimes the kid really needs the team.
It seems to me that you recognize this - you really want to find a role for this young person. Good for you.
Some things I might suggest are research-based. Put him in charge of important, somewhat independent tasks. Have him organize/design the pit space. If the pit design requires the purchase of new components, have him make a bill of materials.
Have him research game strategies and other teams' designs. Hours can be spent on youtube looking at and being inspired by robot videos - have him compile a list of the best teams out there, designs your team may want to emulate, strategies that are effective. Look across years and robot platforms; there may be a very similar game in a different competition (I'm thinking FVC Elevation or VRC Toss-Up) that has applicable methods.
It sounds like this kid thrives on structure and clarity. So whatever task you give him, write it down, clearly and thoroughly, so if he does get confused, forgets where he is, or gets offtrack, he can refer to it and realign himself.
Everybody has the opportunity to be a valuable member of a team.
A quote from a recent FIRST panel discussion that has stuck with me is "Identifying people on the fringes, and bringing them in, is beneficial to the team as a whole." This kid can shine, and shine brightly; it's up to us as mentors to direct the light correctly.
One person who is a master of this is
Jane Young. She is not as active as she used to be, but I bet she's still lurking around these parts.