He wont be sacked I don't believe.
When Brent hired him he said Adams is more than just a manager. He has given him license to rebuild the club. I am thinking for example the improved training ground facilities is something he had an influence on.
I think Brent will allow him to see out the season and IF he takes us down will give him the chance to rebuild for next season. He already states that he works in 6 month cycles with regards to transfer windows so watch out for a massive clear out come January. You may say too little, too late by then but I have a hunch Brent believes in stability and has given Adams 4 years because he believes that he is the best we can currently get for Plymouth Argyle.
Personally, I think John Coleman of Accrington would be perfect for Argyle. Brings through youngsters, works well with a very tight budget and most importantly they play good football.
However, as Adams is in charge I will just get behind him because I think that he will learn a lot from this experience. It may cost us our league 1 status but its up to him to then prove he is the right man to take Argyle forward.