Can you see that someone is in the WLAN when you are in the laptop hotspot?

If I'm in the hotspot of my laptop with my cell phone and the laptop in the WLAN from my house, can you see on my mother's account at 1&1 that my cell phone is also in the WLAN or only that the laptop is in?

Very few cell phones / laptops / PCs can be in the WLAN at the same time and operate a hotspot!

Without additional tools, you can't see who else is using the WLAN / hotspot.
In the router you can always see which device (actually often only the IP and MAC address) uses the WLAN or when it was used.