My son was 4 1/2 when he was finally potty trained. I know how you feel with everyone breathing down your neck. I have found that sitting him down at certain times does help, accompanied with a treat just for trying, or maybe a bigger treat for actually doing it. It doesn't have to be candy, it can also be playing his favorite game with you or going somewhere he wanted to go or getting ice cream, whatever. Of course the going places would be if he at least tries for a whole day. I also used the books and elmo's potty time. They have great books at the library for potty training. Just remember it will happen, and boys are harder than girls for some reason.
The guidance about his readiness is very prudent. It's important that you not be swayed by pressure from relatives or others. Children accomplish toilet training when they are ready to do so - development handles this. All you have to do is be encouraging and supportive, not pressuring or critical. Use rewards to reinfornce use of the potty. Also, use of children's books and videos about potty trainng (e.g., Sesame Street - Elmo's Potty Time) can be very helpful. Searching for a quick remedy is pointless - it is going down the wrong road. If you were to walk into any kindergarten class and inquire how many of the children are toilet trained, all (pretty much) would raise their hands. In other words, this developmental task does get accomplsihed. So relax, be patient.
maybe keep a diary to you get a rough idea of how regularly he goes.you can then take him at set times until he feels comfortable to go.possibly he doesn't like the feeling of the water splashing up onto him.i had that problem with my eldest.try putting tissue into the toilet before he sits down