I believe you’re asking about the same Wi-Fi Chime. In other words, when Duo Cam Doorbell originally launched, it included Wi-Fi Chime, which was always described as being compatible with all other Wyze Cams and doorbells. Then users began reporting that they were buying Duo Cam Doorbell without Wi-Fi Chime at places like Home Depot[1][2]. Then last year Wyze finally began selling the Wi-Fi Chime by itself as an accessory, and I think they changed its name by adding “Universal” when it launched, but my understanding is that it’s the same chime. In fact, after Battery Video Doorbell launched last year, there were a number of Forum posts about Wi-Fi Chime unavailability[3][4][5], because apparently it’s so popular that it was out of stock for a long time.
Your son would have three chime options with Battery Video Doorbell, including the use of a compatible in-home chime, if present, and Chime Controller would be recommended for a wired installation with such a built-in chime.
Does that cover it?