A man of around 45 Yrs old is having teeth problem from 8/9 months

A man of around 45 Yrs old is having teeth problem from 8/9 months. He developed whole teeth sensitivity. He began to treat after a 1st month. Firstly he did teeth scaling. But the problem was not resolved. Sensitivity gradually developed further with difficulty in eating, talking and even while breathing with open mouth​:pensive:. His opg x-ray was found normal. He did all the necessary treatments as per doctor’s advice (Fluoritop mouthwash, Colgate total advance, Ra thermoseal, Sensodyne repair, Thermoseal repair, Salt water rinse).Also he did deep scaling for thrice and used night guard. Night guard worked just for some mornings :pensive::expressionless:. He started getting numbness in some molar teeth. Now he has done RCT in lower middle 2 incisors. During RCT those teeth were found decayed inside. One day he got some relief but again the pain developed. He can’t eat any other food than normal rice. It has disturbed a lot to his daily works and tooooo much mentally.:sweat::sweat:Sometimes he loses hope of life because of this… :sob::sob::sob::sob::confounded::confounded:According to him, doctor told that it might be due to deep biting, so he needs to tie the teeth.
But now he has done RCT, will this tying be successful?? Will it work???
OR is it due to any other neurological cause???

What may be the cause, diagnosis and treatment??? :disappointed_relieved::disappointed_relieved:

Any suggestions please :pray::pray: