What is IRS Jovem and can expat kids benefit?

Short answer: IRS Jovem gives a 5-year income-tax discount for residents aged ≤ 35; eligibility extends to tax-resident expats.

If your dependent children become Portuguese tax residents and enter the workforce before age 36, they receive a phased IRS discount (100% year 1, 75% years 2-4, 50% year 5). Consult a Portuguese accountant — find one via Partners.