Hello Ms Steed,
Elderly people are more prone for Hyponatremia (low sodium). Patients with stroke are vulnerable for hyponatremia due to a possible condition called " SIADH".
As a first step we need to rule out hypothyroidisma nd low cortisol conditions before calling it as SIADH. I advice him to undergo thyroid function tests once. And if possible, serum cortisol test also can be done. Tolvaptan is not really required for him at this juncture as sodium level already nearer to 125 meq/ lit. Give him fluids around 1200 ml per day. If there is a risk of infections then prophylactic antibiotics are also needed.
There is no reason to be overly worried about the sodium levels. This is a common scenario and I am sure your Doctors can easily manage. The patient is more likely to get UTIs frequently. Check his prostate evaluation done. Ask him to eat well and drink water more frequently (if he is taking oral feeds).
So for now I recommend - ruling out hypothyroidism, do a S.Cortisol. Wait and watch approach. Do not rapidly correct the sodium levels. No need to chase the 'sodium' levels as long it is not too low. Remember this is a common scenario and can be easily managed.
Hope this helps
Feel free to ask followups
Dr. Sree Bhushan Raju
MD, DM (AIIMS), DNB, FISN, FICP, FIACM