Seizures can be caused by toxins (unlikely in your case since he’s had two episodes and seems to be normal in between), heat stroke (again, does not apply), hypoglycemia (unlikely in an adult animal that is not receiving insulin), major organ failure (again, he seems relatively normal), brain tumors (your dog seems young for this), epilepsy, or they can be ideopathic, which means that we don’t know what causes them.
The concern associated with seizures is that if they continue for too long, the animal’s body temperature can become dangerously high, causing organ failure and death. You should have your mother keep a log of when the seizures occur and how long they last. Most veterinarians will recommend that if your dog has occasional, brief seizures (3–4/year), that you log them and do very little else because of the side effects of anti-seizure medications.
Seizures that occur more often, seizures that last for more than 1–2 minutes, and cluster seizures should be controlled with medication. Anti-seizure medications must be carefully monitored with bloodwork and will have to be continued for life.
Part of being a responsible pet owner is accepting the financial burden of adequate medical care. Please urge your mother to talk to your veterinarian about this issue as soon as possible.