Flowers can convey a sense of deeply felt empathy so they make the perfect gift to let someone know your thinking of them. Ultimately what flowers you choose will come down to a personal decision but you could bare in mind a couple of possible approaches: You could go down a couple of different routes here.
Either stick with something restrained and tastefully serene or why not go for a more positive, uplifting message with a bold, vibrant arrangement. Bare in mind that ultimately flower-buying is a personal thing so don't feel too bogged down by these suggestions. You still can't go far wrong with flowers as a gift for almost any occasion.