I found where the IRS says that the excluded gain must be included in gross income in determining whether a person has to file a tax return. But, have yet to find a similar statement vis a vis the dependent income test.
Reference: Pub 501 (filing requirement)"Gross income means all income you receive in the form of money, goods, property, and services that isn't exempt from tax, including any income from sources outside the United States or from the sale of your main home (even if you can exclude part or all of it)."
Table 1 notes, page 2. https://www.irs.gov/pub/irs-pdf/p501.pdf
