Based on my opinion, a rindo berry would be a good choice, to cancel out his only weakness "grass", but the only problem is it's a one time item - not repeatedly.
But, since he has high defense, use leftovers. Therefore, he can withstand grass type moves (with his defense) and recover using leftovers or a shell bell.
Rindo Berry - green trees on route 5,7,10,11,19
Leftovers/Shell Bell - Route 12/Dendemille city
Sources: 1 and 2
Hope I helped! :)