Love don't prove it live. Try to be around as often as possible to talk with your lover about what you both. Not worth the work bring to the fore to the detriment of his personal life.
Make a loved one smile, at least a little, the joy of giving, especially when it is no laughing matter because of the problems. Just don't joke about it, joke can be cruel and lead to a quarrel.
Gifts, not necessarily expensive, little things made with your own hands. They can cheer up not only you, especially if you guess the preferences and interests of the guy.
Devise a signal that will only be understandable to you two, and would mean: "I love you!" So you will be able to remind him of his sympathy in any situation, and understand your gesture will be only a favorite person.
Learn to be attentive, active listener. Even if you are very busy, it is enough to periodically nod and smile if this is a joke, sympathize, if it's a serious conversation, you can touch. Not necessary to answer every line with words.
Often hug her beloved boyfriend, often affectionately touch him. Even just passing by, shake hands, Pat on the shoulder. It is better than any words will say about your attachment.
Doing all that he believed in your sincere love, do not ask anything in return. It will take time before people will begin to understand and appreciate all your efforts. Or maybe he just hasn't learned to Express their feelings as openly as you do.