Hi S.,
I was going to suggest what Karen did--present a landscaping service for a day as a gift(no pun intended).
I'd get him a card, some balloons, and either that morning, or evening, make him a special meal.
I'd say something like: "you work so hard and make the yard look so nice. I wanted you to not have to worry about it, to be able to focus on getting well, so I called so and so to come out for you just this once. This way, it won't get away from you while you're getting better, and will be easier for you to tackle when you're able." Something along those lines.
Someone getting so thoughtful a gift would be hard pressed to get angry about it, even if it's not done to their standards.
I'm the same way when it comes to housecleaning. I like things done a certain way, but if my hubs called a housecleaning service to do it for me just one time even, I'd be so grateful for the help(and I'm not recuperating lol)!
Maybe when your hubs *is* better and back to doing the yard himself, you could go out with him and ask him to show you how he does things, and why he likes them a certain way so you can understand. If you want to help him in the future.
Best of luck to you both, and I hope your hubs gets better soon!
K. W