COPD and frequent serum sodium depletion

My Medical History 0
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I am "Thomas" a 69 year old male from Kerala, India. My breathlessness was diagnosed as emphysema 5 years ago, and I was asked to use a bronchodilator "Maxiflo 250 Inhaler" (Formoterol + Fluticasone Propionate) twice a day.

My Serum Sodium level has gone down below 128 mEq/L four or five times in the last 4 years. Whenever the problem occurred, my pulmonologist and physician have prescribed 'Tolvaptan' or 'Natrise', and the sodium level used to come up after taking these medicines for approximately 10 days.

The doctors have asked me to limit my fluid intake to around 1 litre. Since the last 4 months, my sodium level went down on 3 occasions, and I'm feeling UNCONTROLLABLE THIRST.

Also, I feel severe fatigue, difficulty in breathing, and heaviness in the chest and insomnia. I see vivid dreams almost every night (not nightmares) which makes me depressed.

MY TESTS
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My latest RFT, LFT, Thyroid, and Echo cardiogram results conducted 2 weeks back were perfectly normal.

Two years back, I became a diabetic patient, and my latest HbA1c value is 6.9. I take One "Torglip M 50/500 Tablet a day (Metformin and Vildagliptin).

For blood pressure I take 1 "Olmezest 40 tablet" per day.
(Olmesartan Medoxomil)

A CT scan of the lungs was done in Dec. 2023, and nothing else was detected except emphysema.

Results of my sodium test done 3 weeks ago.
a) Serum sodium: 129 & Serum osmolality: 269
b) Spot urine sodium: 64 & Spot urine osmolality: 241

ADDITIONAL INFO
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1) I suffered from a mild attack of "Transient Ischemia" in the year of 2005 when I was 47 years old.
I was treated in KEM Hospital, Mumbai, and the diagnosis was a slight occlusion in the left external carotid artery. I've been taking a tablet for Cholesterol" tablet and one "Aspirin & Clopidogrel" tablet every day, and there was no recurrence of TIA for the last 21 years.

2) I suffered from a head injury resulting in a skull fracture due to a motorbike accident at the age of 27 (in the year 1984). The treatment was also in KEM Hospital, and I became alright after a treatment of 1 month.

NOTE:
Until the physician I consulted one month back, so far nobody has gone into the root cause of the periodic depletion of sodium. The treatments were always the replenishment of sodium and restricting water consumption. My physician has asked me to freshly consult a neurologist, pulmonologist, and cardiologist.