hello and thank you for asking HCM,
I understand your concern and if these symptoms progress than it's possible that your father is accumulating fluid in his peritoneum
, so called ascites
. My advice is to visit your GP or your gastroeneterolgist and ask them to try to do tests to see if it is ascites or not and do ascites puncture procedure if it's needed.
I hope this asnwer was helpful to you.