Is it ok for a 70+ years old to take a litre of energy drink lucozade everyday for a month?

No. Most energy drinks contains large amounts of sugar and caffeine. Drinking a liter a day of this could cause high blood pressure or heart problems as well as weight gain.
Energy drinks. I read up on this I couldn't find the normal quantity 1 l seems like a lot it's a very old energy drink1929. These discussions need to be long and detailed. On the other hand you have to ask yourself why you need this type of supplement why is a couple cups of coffee not sufficient? And other questions. There are other very detailed ways to go about improving your health and your energy.