Seriously? In a large scale disaster (hurricane, earthquake, etc) you would be irritated by getting a free text telling you...[whatever]
Why should he need to explain his reasons to you (or to anyone)? If he doesn't want to receive such a message on his phone, why shouldn't he be able to block or reject it? You'd rather force the message on him because you think it's a good idea, even if he doesn't?
"An idealist is one who, on noticing that a rose smells better than a cabbage, concludes that it will also make better soup." - H.L. Mencken