I think you've made the best decision, Dej. He has heard from you that you care about him; you are reaching out in the healthiest way for you by sending cards/flowers. He will appreciate it.
You need to take care of your health, and the stress of dealing with dysfunction, IMHO, will set your health back.
Send prayers of gratitude for the love this man has shown you, and pray that he will be at peace without feeling more heartbreak at the hands of his offspring.
Just goes to show family isn't always about the blood coursing through our veins...you are his family; bless you for caring