His first thoughts, though, are with Glenn Roeder and he says of him being taken ill on Monday: "It was a shock to me. People don't really expect things like that to happen and all the lads are obviously concerned.
"He is a nice man, everyone's friend as well as being a colleague. We all hope he is going to get well and hope, please God, that he will be all right.
"There is not much you can do. All I would think the gaffer would want, although he is ill, is for the lads to just focus on the next three important games - but we just hope he recovers soon."
As for Trevor's appointment, and echoing the thoughts of the other players, he says: "It's good because Trevor has been there and done it. He is a nice man and all the lads know him - everyone has a good relationship with him.
"He is at every game, and comes to the training ground, and I am sure it will be good, but we don't need anyone to motivate us now - we know what we need to do, and we have to look to do doing that."
Both Trevor and MD Paul Aldridge spoke to the squad at Chadwell Heath on Thursday, and Jermain says: "He got us all together and said to the players 'basically, we need to focus on the next three games.'
"We will not think about anything other than winning on Sunday. There are going to be chances in the game which hopefully we can take and we will be going there thinking we can win - it might be unbelievable, but it is possible.
"The thoughts are on winning, nothing else, and if we can win our last three games, which I definitely think we can still do, it will be enough.
"With the manager being ill it is one thing after another, but hopefully we can get out of this situation and, like Trevor said, bring a smile to everyone's faces again.
"At the end of the day, we are the ones that have to go out there and perform - it does matter who the manager is but on a matchday we are the ones it is down to, and no one else, once we cross the white line."
Jermain may have been just one year-old when Trevor retired, but he says: "I have seen clips of him and from what I have heard he was a bit special - he's a legend, he has been around football for years, and I am sure he has good ideas."
Although stressing again that Jermain's thoughts are primarily with Glenn, on football matters, and a weekend which produced a win and a draw, he says: "I was glad when we won the game against Middlesbrough though it would have been nice if Bolton had lost as well - but we needed the win.
"We showed a lot of bottle on Monday because it was pressure and the boys did the job. You think about it before but once you are out there you just get on with it and approach it like a normal game."
As for the Bolton game, and the media coverage it attracted particularly pertaining to alleged incidents afterwards, Jermain adds: "There was a lot of controversy, but at the end of the day the lads were fired up because the game was so important.
"To be honest I didn't see what happened but Joe is not like that. It is out of character for Joe, he hasn't done it before, and it was just frustration - which is how people should look at it."
As for his own desire for a goal, he says: "I have gone three games without a goal but before that I went on a good run. At the end of the day I am a goalscorer and it doesn't really bother me - I know when I get another chance I will put it away.
"I didn't really have a clear chance on Monday, I just worked hard for the team and we got the win, so there is not much more to be asked."
And would he stay if West Ham were unable to retain their Premiership status?
"Yeah, obviously you can't really say in football, but at the end of the day I am happy here and when you are happy at a club there is no need to think about anything else, really.
"I am happy and I just hope we don't go down because it would be nice if all the boys could stick together."