PhD Advisor not responding to emails for letters of recommendation

Question

I am an immigrant in US and graduated in 2018 from a good public university on the east coast. I had a cordial relationship with my advisor during my PhD.

Currently, I am working on my immigration application that requires letter of recommendation from the advisor. He replied to my initial few emails saying that he will get the letter over the weekend/soon and after that have gone completely missing-in-action.

I have been chasing after him for almost a year now. His email is definitely working and he is super active on Twitter. I also dropped him a couple of texts on his cellphone just to be sure.

What are my options? Shouldn't the advisor have ethical/moral responsibilities? especially considering the dire immigration circumstances, and the effect this application can have on my and my family's future in the US.

PS: He is also an immigrant from the same country as mine.

Edit1: I wish it was easy to just meet him in-person. Not only are we on opposite coasts, but he is also not coming to the lab/office these days due to COVID.

Edit2: Should I raise this matter with Department Head? (My advisor is a senior professor who helped department head become department head)

Answer 1

You may try to either visit him during his office hours (more or less Krebto's suggestion) or you might contact someone at the department who is in close contact with your advisor. The latter worked for me a few years ago when I had to get in touch with someone who simply ignored my (and other students') e-mails. After a few weeks, I asked a colleague of his to remind that person to respond to my message. That middleman should be a friend of both, yours and the advisor.

However, as you have been sending him messages for a year already, it looks like your advisor simply does not want to write that letter. If you keep pressuring him, e.g. directly in person or through a colleague, you might eventually get that document. But its wording might not be as nice as you had expected in the first place.

Maybe, you could also ask nicely, if there are any issues that the advisor wants to clarify before sending that letter. Those might be some details regarding your research.