I really appreciate your care & concern for well being of your father.Although you have not mentioned all details, I assume that your father has Chronic kidney disease
Dialysis is a treatment which is instituted only when essential & becomes life-saving for the patient.Every patient may not tolerate the dialysis well & that depends on many factors.
I strongly feel that your father needs thrice a week dialysis against twice.
His tolerance may become better there after.
If he is very much scared of hemodialysis
,you can switch over to CAPD.
I strongly advocate you to continue dialysis.There are various diet plans, drugs available which can lessen the bad -effects of dialysis.
THere is no substitute available neither in Ayurved nor in Homeopathy
for dialysis,however these drugs may help a person tolerate dialysis better.