Apple now designs its own modems, and its TSMC that fabs them. OP is asking if Broadcom might start fabbing those modems. This is not the case here, but you seem to ignore the fact Apple is a modem designer now.
No; the person I replied to line about "having to transition these by the end of the year" was a reference to a fact that Apple's publicly announced deal with Qualcomm expires this year/early next year.