grammar - Is this a proper use of a semicolon and the word "whom"?

PCAs are usually assigned to an individual with a physical, mental, behavioral, or emotional handicap; whom they work with throughout the year.

Is this sentence grammatically correct? I know that semicolons are sometimes used when you have a list at the beginning of the sentence, to prevent confusion. Is that accurate?

Also, would "who" or "whom" be proper in this usage? I thought it would be "whom" because it's referring to the person who is helped, not the person who is helping, but I am not completely sure.

Answer

No, you don’t want a semi-colon there. A comma will do. Whom is grammatical, but so, too, would who be in an informal context.