So my theory is this Candace is insane. Phinease and ferb actually died in a park amusment accident along time ago. She made up Isabella, Buford Baljeet,and Milton. She even made Isabella have a crush on Phineas. That's why she made all these notions that Phineas and Ferb are making inventions is that she can entertain herself and say in her mind they are experts on building studd so they couldn't have died in a roller coaster accident. That's why her mom and dad are never home. They can't get over the pain of losing two sons. Her mom is always shopping and Her dad is always at work. Her friend stacy encourages this because she knows Candace is just trying to cope with her brother's deaths. Her mom though does not put up with it when she gets home she never sees the inventions or the boys. She does feel candance's pain and says oh hello boys and perry. Jermey Johnson is not her boyfriend. He is her psychologist doctor who she fell in love with. She devolved and gave him a teen body in her warped mind. Major monogram and Carl the intern are two men who help with the pyshcolgoy coping class.
is a crazy scientist who believes his inventions work. He became insane due to a lonely/horrific childhood where he was abused physically and mentally until he ran away to America. His brother the mayor was never his brother. He invented the perfect brother thing in the back of his scared mind in attempt to have someone to compare himself to. In all reality Roger was really just a perfect version of Heinz that had invented in his mind. A role model to the scarred boy. So to exceed and outdo Roger (his non exsisting brother/rival) he began inventing. His inventions are really just made of cardboard and junk. Even when Heinz immigrated to America to try to cope with his insanity he kept Roger as his rolemodel eventually making him mayor of the tristate area. He has met Candace once at their pyshcology class. He had brought along a pet platypus so she (Candance) thought it would be cool if he was their pet and at the same time a secret agent. So she added him as a family pet and named him perry after the person who sits next to her in the coping class . Vanessa Doofenshmirtz is Dr. Doofenshmirtz's daughter but in reality his young daughter. She is not even close to being a teenager. was a doctor who made up the stories of a tragic childhood as a excuse for his insane projects. He also made up norm who is supposedly his advanced robot who in reality is a toy wind up robot he lost as a child. Ballooney is just that a balloon. He gave the balloon to his daughter Vanessa but she didn't like the ugly face on it. So he kept it and since he was lonely he called it his friend. His building Doofenshmirtz inc. is just a apartment where he lives and barely can keep a room there due to him buying large amounts of cardboard for his "anators."
Lastly Her dad (Lawernce) copes with the boys death by being weird and having major interests in boring and weird things. This habit though of antiquing began to become an obsession Lawerence began leaving his wife to statewide events. His wife (Linda) was not pleased though and demanded he stay with the family during the hard times. He solemnly agreed and watched old re runs shows from his childhood. In the process trying to keep his mind off his boys tragic death in the roller coaster accident. One day though he caved in to insanity just like Candace He began seeing the boys again and eventually their inventions. He now also daily attends classes with and Candace.