Hi jellybean and welcome to the forum.
This must be very scary for you and to be honest it seems like he may become very disturbed if you mention to him that he needs help......in fact I suspect he won't be able to accept it as he is already losing touch with reality.
You have a couple of options. You can phone your own GP or his and talk to them about what to do and ask if someone can come out to the house to see him.
You can phone social services and tell them and they may well send someone out to make an assessment.
I do think he sounds like he needs help ( you don't need to be troubled over why this is happening at the moment - it does not matter why...), and since he has not got help for himself someone else has to do it for him. Please do not wait......do it tomorrow.
You also need to be sure you get help and support for yourself. Staying on the forum, by phoning Rethink or Mind helplines, and by contacting a carers group in your area....