Outdoor rabbits tend to do best when housed in pairs to prevent loneliness. Even 3 hours a day with a human, leaves 21 hours per day all alone. But you have a couple options.
One option is to temporarily have him housed indoors where he'll have people nearby (even if they aren't directly interacting). Just being in the same room while people watch tv or go about their business inside their home is still similar to bonding time.
The other, more permanent option is to consider getting him a bondmate. An already-spayed female from a rabbit rescue is a potential way to go. Already-spayed rabbits are cheaper than the cost of a spay. Also your guy could meet some potential rabbits at a rescue to pre-screen for potential compatibility.
I don't know whether you'd have time to go through a bonding though before you get busy this summer.
