Thyroid medication should be taken on an empty stomach, with a full cup of water, then wait at least 30 minutes to an hour before eating or drinking anything else.
It's not the vitamin C in broccoli that causes issues; it's the fact that broccoli is a goitrogen, which interferes with thyroid function.
Vitamins/minerals should not be taken within 4 hours of thyroid medication, especially, calcium.
If you take Synthroid/Levothroid etc.. To soon after you've eaten or eat food high in Vitamin C (broccoli) etc ..... You could deplete all your medicine. It is very important to take your medicine one hour before meals or two hours after your meals. This will safety allow proper absorption.
Out of context this is confusing. I'm sure the lab results will answer your question in a short time.
We can presume what he was thinking, which is merely a guess, and could be more confusing, or you can wait, which makes more sense.
The outcome will be three things; raise med, lower, or stay the same. Not to worry.