Jokes in SMS should be short and deeply meaningful. But you can make your interlocutor laugh with a joke split into several messages. Try to make the guy laugh with a series of SMS, gradually revealing the idea of the joke.
Write your future joke on paper or in a text editor as a story from short, capacious sentences. Avoid complicated phrases, participles and participles. Use adjectives to a minimum. Count the number of characters with spaces in each sentence. There should be no more than 140 of them. Each sentence should have more tension and pressure than the previous one, and in the last one the joke should be revealed in an unexpected ending.
As methods of humor, use violations of logic: combining incompatible, giving hyper-large or hyper-small sizes to each object. Try not to spread the joke on a page and a half, fit it in one or two paragraphs. Firstly, it's cheaper (send less SMS), and secondly, a lengthy joke is not so effective. And you still won't use all the available means of humor in one story.
Send one sentence by SMS every 10-30 minutes. Wait for the reaction after the last SMS. Most likely, you will be able to make the guy laugh.