Hi.
Welcome to our Group ... though I'm sorry you need to be here.
Kidney failure is such a difficult illness and it is impossible to say how long Boey might have, without access to a huge amount of information. This includes all the latest blood test results and urinalysis. If you have these, please post them.
Also, did your vet perform a blood pressure check? If not, it needs to be done.
Seizures are not uncommon and can be caused for a number of reasons, all associated with the kidney disease. In may cases, it is due o abnormal sodium, potassium, magnesium and/or calcium levels. The blood tests will help identify if that's the cause.
They can also occur due to neurological changes - the disease can disrupt nerve pathways, which the causes seizures to occur.
I would suggest you have a read of a few of my articles, which I am sure will help you plan how to manage Boey's illness. Of course, you need a good vet to support you too. Diet is extremely important - so make sure you read that one, if none of the others. Get back after you've read these articles and ask any questions you may have.
http://www.infobarrel.com/My_10-Point_Plan_for_Dogs_with_Kidney_Failure
http://www.infobarrel.com/How_Diet_Affects_Dogs_with_Chronic_Kidney_Disease
http://www.infobarrel.com/Changing_Diet_During_Canine_Kidney_Disease
http://www.infobarrel.com/Tremors_and_Shaking_in_Dogs_with_Kidney_Failure
Hope some of this helps.
Tony