guacamole is always good, all that avocado, some tomato, maybe some onion, depending on his preferences.
will he scoop or just dip? Fruit salsas are great if he'll scoop, but just dipping they don't really work. Pineapple, mango, strawberry, peach, cantaloupe... they all make some good salsa.
Take a block of cream cheese and add stuff to it:
chopped cooked (wrung dry) spinach
chopped green onion
crushed garlic
chopped (drained) tomatoes
grated carrot, zucchini
Finely chopped celery
chopped boiled egg
mashed roasted veggies (eggplant, onion, cauliflower, tomatoes, asparagus, etc.)
chopped artichoke hearts
You can do essentially the same with sour cream and/or yogurt and/or mayo... mix and match as you like (some dips I like better sr. cream/mayo, some yogurt/mayo, some get all three).
Some dairy-free options:
Hummus (garbanzo bean and tahini with garlic)
Baba ghanouj (roasted eggplant and tahini with garlic)
Olive spread (chopped green and black olives with garlic and olive oil)
Tomatillo salsa (pureed steamed tomatillos, onions/garlic, with or without tomatoes)
Some of our favorites (although not really containing veggies) are:
Curry crab dip (yogurt/mayo, crab meat, curry powder)
Clam dip (cream cheese/mayo, clams, worcestershire sauce, green onion)