Don't make a big deal of him being fussy and don't force him to try new foods - it can often be counterproductive in the long run, turning a bit of fussiness into a real problem.
You could try serving family meals "help yourself" style, with food in serving dishes in the middle of the table and everyone dishes out what they want. If they have the control over putting something on their plate and see other people enjoying the food, they can be tempted to try something. Don't go overboard on the praise if they do, just make a comment on how you like the taste or something.
Get him involved in choosing what you eat, shopping and cooking. You could chat about healthy foods in a very child friendly way, as in milk gives you strong bones, potatoes give you lots of energy, meat helps you grow strong muscles etc.
I know it's easier said than done but don't stress about the situation - a doctor once told me that if they are growing, not losing weight and have enough energy to do normal toddler stuff then they are getting what they need even if their diet seems limited. Giving them a multivitamin is a good idea too.
I read a really good book, I think it was called "first tastes - how we learn to eat" by Bee Wilson, it goes into the reasons why people may be fussy or even food phobic and gives you lots of ideas about helping to solve the problem.