Golf courses set their own social distancing rules. Some only allow one person in a cart at a time (unless from the same family) some only allow pull carts. You have to bring in your own wagon type pull cart if riding carts are not allowed and there are no rentals left - because there will be no caddy's carrying your clubs.
The point is, golf courses set up the rules so you need to call the specific golf courses he will be on. Best to do this now rather than get there and find out you can't rent something you need.
Michigan golfers getting creative using carts on the course
“Caddies, starters, and golf carts may not be provided, and clubhouses, pro shops, driving ranges, and miniature golf courses must remain closed.”
How U-M Golf Courses Resumed Operations Amid Global Pandemic - University of Michigan Athletics
University of Michigan Golf Course:
To begin the season, knowing full well that information changes daily, they came up with the following guidelines for all players:
• Tee times must be booked in advance over the phone, and payment is required at booking.
• Golf carts are available for single riders only unless there are two players from the same household.
• Carts are thoroughly cleaned and sanitized after each round.
• No clubhouse access.
• No rental clubs.
• Flagsticks are not to be touched or moved. Small foam noodles, like those seen in a swimming pool, have been fitted around each flagstick to prevent the ball from dropping all the way into the hole.
A modified hole at U-M Golf Course
• There are no ball washers, benches, bunker rakes or water coolers on the course.
• Players are instructed to arrive no more than 10 minutes prior to their tee time. Gathering in groups before rounds is prohibited.