I understand that you are concerned about your fellow ingesting an Advil (ibuprofen) tablet, as ibuprofen can be toxic for dogs.
At 30 pounds he is about 13.63kgs, so he ingested about 7.3mgs per kilogram of body weight (100mg/13.63kg = 7.3mg/kg) which is under a toxic amount.
From the ASPCA database:
◾25-125mg per kg of body weight – symptoms include vomiting, diarrhea, abdominal pain, loss of appetite, stomach ulcers;
◾more than 175mg per kg of body weight – the above symptoms plus blood in the stools, acute kidney failure;
◾more than 400mg per kg of body weight – the above symptoms plus seizures, coma, disorientation;
◾more than 600mg per kg of body weight – death.
Given the amount he ate I don't think you need to do anything as far as inducing vomiting, or worry about true toxicity. You might see mild gastrointestinal upset if he is especially sensitive, but that should be it.
At home now to try and decrease acid production in his stomach and lessen any possible symptoms you can give either:
1) Pepcid ac (famotidine) at a dose of one 10mg tablet per 20 to 40 pounds of body weight every 12 hours (one 10mg tab for him)
2) Prilosec (omeprazole) at a dose of one half of a 20mg tablet per 20 to 40 pounds of body weight every 24 hours (one half of a 20mg tab for him)
These are acid reducers that are found over the counter at the drug store. They can be given as needed.
If his stomach seems at all upset to decrease the symptoms you can feed him a bland diet for the next several days. A homemade bland diet is a mix of 1/3 boiled minced white skinless chicken or lean boiled hamburger and 2/3 boiled white rice mixed with some low salt chicken broth to make it easy to lap up and swallow and get in plenty of fluids. Feed small meals frequently.
Things to watch for that mean trouble include vomiting, especially blood tinged, dark, black or tarry stools, or frank blood in the stools, lack of an appetite, increased water consumption and urination. But I don't think you will see those given his weight and the amount he ate.
Please let me know if you have any further questions.