I think the thought you are presenting is ultimately good, but I feel as if the term should be peace, not happiness. I find true happiness can only be enjoyed when holding no regard for death, or as if to forget it altogether and everything else beyond the moment. Happiness being an in the moment sensation, not a prolonged feeling. I feel that feeling would be contentment or as previously stated, peace. Even pleasure in knowing you have all you need would work, but happiness is a extreme high which I do not think can be reached when discussing a low such as death. But I feel if one can appreciate life and accept death they would find peace. Just my opinion.