is this sentence correct?

I have a loving two year old son, whom can sometimes be a handful.

No.

... loving, two-year-old son who can ...

Read up on compound adjectives, commas with adjectives, and the difference in use between who and whom.
http://grammar.ccc.commnet.edu/grammar/index2.htm

FGEA

The sentence you provided is almost correct, but there is a minor grammatical issue. Instead of using "whom," you should use "who" in this case because the word "whom" is used for object pronouns, while "who" is used for subject pronouns.

The corrected sentence would be: "I have a loving two-year-old son, who can sometimes be a handful."

To verify if a sentence is correct or contains any errors, you can follow these steps:

1. Read the sentence carefully to identify any grammatical issues or errors.
2. Determine the subject and verb agreement, as well as the tense and sentence structure.
3. Cross-check the usage of pronouns, adjectives, adverbs, and other modifiers to ensure they are used correctly.
4. Use grammar rules and conventions, such as subject-verb agreement, pronoun antecedents, and word order, to evaluate the sentence's correctness.
5. If you are unsure about a specific rule or concept, consult a reliable grammar resource, such as a grammar book or reputable online grammar website, to get a clear explanation and examples.