Go slow. I am very glad to hear he has been eating and drinking and perked up. If a bunny stops eating it is an emergency and you need to do whatever you can to entice it to eat. Fresh greens are great because they contain a lot of water. Herbs are good (parsley, cilantro, fennel camomile, etc... ) or dandelions from the garden... At that point almost any food is better than them not eating. Once the rabbit is feeling better and eating more readily, go back to normal feeding: unlimited clean hay, mainly, a very small ration of pellets only. If you decide you want to feed fresh greens from the garden you have to be consistent. Start with just a few pieces and slowly build up to a handful or so. From then on it is best to continue feeding the same amount, at the same time, every day. Bunnies have delicate digestive systems that are easily thrown off... Also make sure your rabbit gets plenty of exercise every day (traditional rabbit cages are way too small!), running, jumping, etc... to keep the gut functioning well.
A water dish, elevated so it’ll stay clean, is much better than those bottles - your bunny will drink much better from that.
Good Luck!