If he got his citizenship through his parents or birth, yes.
You must apply by sending the appropriate documentation and fees to a "Conservatória de Registo Civil" or to a portuguese consulate in India.
You should have received an email about being granted settled status with an attachment that explains among other things your rights to apply for U.K. citizenship. Rules based on “indefinite leave to remain” are not relevant anymore.
What the governent website says: "To apply for citizenship with settled status you must usually have lived in the UK for 12 ...