Cat dental advice / help

Hi there I’ve noticed my cat has started to loose his teeth his bad breath and his tongue hanging out . My cat is around 12 years  old he was a rescue and didn’t have a great start his  not a  people type of cat normally, we have never been able to brush his teeth his always been quite vicious we avoid going near his mouth, his become   more social that was another one of my warnings that something might not be right with . I’m concerned cause his vet has closed down/ gone out of business and the financial cost of getting him checked  worries me but I’m also concerned about my cats health I have bought water dental care and paste , we have changed food to small striped or soups cat food  to help him but think he need to be seen .