It can sometimes be hard to get budgies and cockatiels to eat fresh foods. I think it's partly because they eat a much more limited diet in the wild than many other bird species, and have more trouble recognizing that unfamiliar things really are food.
Eating them in front of him may help. Letting him see another bird eat the fresh foods in probably the best way, but not always possible. Something that often works is to chop up the fresh food small and sprinkle a bit on a mirror so he sees 'another bird' eating.

He may also enjoy a bunch of freshly washed greens hung up in his cage or in a pile on top of his cage - a combination fresh food and bath! Being from dry climates, the main way they get baths for much of the year is by leaf-bathing in dew covered grasses.
Really, whatever your bird prefers is the best bath. No need to use special bath sprays. A shallow dish of water, wet leaves, or a misting bottle can be used. If he won't bathe on his own and dislikes the misting bottle, you can try just a gentle misting every week or two. If he doesn't like it there's no reason to do it more often than that.

Karen
Chico (conure) and Pippin (budgie)
WI