matrix has a web interface and there’s many different options for clients. https://matrix.org/ecosystem/clients/

there’s also signal but idk if that will suit your needs

there is revolt that is like discord but it is open source. downside is it is not e2ee

tie him to a chair and make him watch this

https://yewtu.be/watch?v=MBBOjf7fLrc

(I’m joking about tiying him to a chair ofcorse)

it even comes with a removable battery, Sim card slot, and SD card slot

google pixels sadly are the best device for any custom ROM. if you really don’t want to use google and your willing to sacrifice some performance and quality of life I’d recommended the fair phone 5 with /e/os. it is easily repairable and has I think 7 years of support. ofcorse it sacrifices a few qol things of most modern phones like the top end displays or the best photo quality and it costs the same as a google pixel 8 but its all ethically sourced and is a extremely good project and product. I’d reccomend watching reviews first “not Linux tech tips” the software updates fixed most of their issues anyways.