What would you do to prevent the elder sibling from feeling left out upon the arrival of newborn and mummy is doing confinement?

My friend tried as much as possible to spend alone time with the elder child (e.g., putting her child to bed) every day. She also reassures him that mummy loves him very much. Explaining to her elder one (every now and then) that he is now a big brother and got to help mummy look after his little sister also helped.