Be sure and give him your forwarding address.Yes, texts are legal in court, as electronic forms of communication are considered to be "in writing."

The fact that she responded and said she got it - shows she did get notification.Here's the Illinois law that says electronic communications satisfy any requirement that something be in "writing."

I was able to get a tenant to go from money orders to an electronic pay option.

I use Buildium, and almost all of my tenants pay electronically, and I can pay my owners electronically.  

Bank transfers are typically online where the tenant sends funds electronically to you if your bank offers the service.  

Cash, money order, electronic payment.

Even a text from them saying they have vacated should be fine for legal notice, as electronic communications are accepted in most states now.If their phone is still working, they should respond when they see you can keep charging them rent.

I would like to go electronic but my tenants are resistant.One tenant banks with Chase (as do I).

I don't just want the rent to come in automagically and electronically, I want the application fee, the security deposit and any other $ to follow the same path.  

If the place is indeed empty (no food, clothing, medications, personal electronics, etc.), and the father himself has turned off the utilities, it's considered abandoned.