Your father in law has to take his BP medicines regularly. Let him not miss even one. In addition we recommend the following tips for better BP control and good health.
1) Restrict intake of salt. Avoid foods with added salt like chips, mixtures etc. avoid any processed or packaged foods as almost all of them have added sodium. This is the most effective measure to control BP is daily exercise, like a brisk walk for 30-40 minutes every day is good. If he already has a regular exercise routine, like jogging he can continue that instead.
2) Low fat diet- cut down on oily and fatty food including milk products. Avoid high sugar foods as well.
3) Drink adequate amount of water- at least 2 liters per day to keep the kidneys and bowels functioning optimally
4) If he smokes- getting him to stop would be very good for his health and would lower his risk of heart and vascular disease
He can take a multivitamin
regularly. As you age the amount of nutrients absorbed from your diet gradually decreases. He can take any supplement that is manufactured by a reputed company as that will be of better quality. Example Riconia- This has to be taken just once a day after food.