YABU, and I'm dismayed to read this is coming from a former teacher. The state of language education is dismal in England, and it is largely due to ignorant attitudes like the one you display.
How much time is 'a lot'? The more language exposure children can have, and the earlier, the better. Think of how a child learns English - through thousands and thousands of hours of listening, then speaking words, making phrases and finally sentences. I think the golden number is around 10,000 hours.
You hope to replicate a similar level of comprehension through one hour a week? In terms of language skills, one piddly hour is next to useless, although it may have some value if it sparks the children's enjoyment for languages.
Languages might seem worthless or unnecessary for you, but that's your ignorance showing. You're doing him as much of a disservice as if you believed that maths was a waste of time because we have Excel and calculators. Stop projecting your own misconceptions and paranoia about languages on your son.
Languages are the key to understanding other cultures and values, religions, important events in history, understanding English and enjoying international literature. It's great for sharpening your wits and having a good memory later in life. It's a great feeling when you can talk to someone in their language, and that without your skills, you wouldn't be able to communicate.