My pregnant sister has swollen feet and she is in 3rd trimester, how can i help her?

Encourage her to do simple exercises like: 1) bending and stretching her feet up and down 30 times or/and 2) circling each foot one way 8 times and subsequently the same the other way. Aromatherapy might help too. Some essential oils like lavender and camomile can ease the pain and help her relax.