Hi smurfchops! He might not have an infection, sometimes water can just get trapped in the ear after swimming, shower or bath. I know what he means by being able to feel it when he presses the ear, this is because he is compacting the water - tell him not to!! if there is an infection the doctor (normally nurse) will not syringe it until the infection has cleared up and will probably prescribe a course of antibiotics in the meantime.
I would however warm a teaspoon and put either some almond oil (can be bought at a chemist) or oilive oil on the spoon and into the ear. Then place plenty of cotton wool in to keep it in. When he goes to bed and lies on that ear he will probably find that when the oil comes out it forces the water out to. Help him with putting the oil in as it is hard to do on your own.
Hope this helps