Hello and welcome to HCM. As an 
Urologist, i can understand your concern. 
Maintainence 
dialysis to maintain 
kidney function,vomitting is common.
The causes are various, including electrolytes disequilibrium,drug reactions,B.P.fluctuations,etc.
The safest step is to avoid home or OTC remedies and take him to hospital.
His tests will tell us the cause and start treatment and dialysis if needed.
He should take low salt and protein diet,avoid fresh fruits and take all drugs.
Maintain fluids intake,according to urine output only.
If you've any doubts,send all the reports to me,as a direct question.
Dr.Matthew J. Mangat.