Options to Boost Phone Signal for Nice Aunt in Nursing Home?

Try using a phone as a hotspot at the window and a second phone connected by WiFi with WhatsApp for calls.

The drawback is that everyone she calls would need WhatsApp too.

If that worked then use a router by the window instead of phone hotspot.

Alternatively, use the phone socket on the router to connect a standard landline phone which can them use the router SIM for calls. Some routers have this enabled, Huawei are probably the better brand for having phone call capability.

Also try Vodafone and 48 / 3 for reception as they might be better than Eir in that location.

Signal booster is a non runner IMO, too expensive and would probably need permission from nursing home owner.

"during the call, connection drops from 4G to 3G and if 4g enforced would not work"

Do routers have capability for 2G calls if 3G ends in the next few years?

Good question.

Looking at datasheets, B593 does list EDGE/GPRS/GSM (2G) where two later models only mention UMTS/WCDMA(3G) as alternative to their 4G capability

I guess(and hope) by the time 3G will be ended, we might have VoLTE, other than that, roll back to "stone age tech" or no calling from router 😎

If the Nursing Home have good WiFi in your aunt's room, your best option would be to use WiFi calling. However, as you have suggested, your aunt will need to change to Smart phone that supports WiFi calling. You should check it on your own Smart phone first, before changing your Aunt's phone. WiFi calling requires very stable WiFi - particularly on the uplink - so if too many people are sharing the WiFi in the Nursing Home, it may not be good enough. You will need to test it.

If the WiFi isn't good enough, you could try the option of using another phone or router near the window to create your own WiFi hotspot from mobile. However, I am doubtful that your mobile coverage is good enough for this to be reliable, since you have stated that the mobile coverage in the room is already weak, even for voice calls. Higher speed data for a router will require 3G/4G/5G, and these are less likely to be satisfactory than the 2G for voice calls. It is likely that the Nursing Home is well insulated, and the windows and walls are blocking mobile signals.

If the 2G mobile signal is good enough near the window, you could consider using a fixed cellular terminal. I haven't used this model - but something like this might help. You can insert your Eir/GoMo SIM in the terminal. It likely has a higher gain antenna that your aunt's phone, and it can be left in a location in the room where the 2G signal is best. Your aunt can then use a normal corded or cordless phone which will work off the fixed cellular terminal.

https://www.amazon.co.uk/Wireless-Terminal-Platform-100-240V-Security/dp/B07STWDWT2/ref=asc_df_B07STWDWT2/?tag=googshopuk-21&linkCode=df0&hvadid=499222326876&hvpos=&hvnetw=g&hvrand=6430983374345085830&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007850&hvtargid=pla-1377236473912&psc=1