Praise the Lord he is feeling better. What a HUGE blessing!!
To ferment your own kefir, you need kefir grains, but once you have them you just put them in milk (I prefer the higher fat dairy, makes the kefir smoother) and leave them to ferment on your counter. Once they are fermented you take the grains out and then you can put the kefir in the fridge.
Look for Doms kefir site online, it tells you EVERYTHING about fermenting kefir and where to get grains. I wouldn't spend over $10 for grains, but look and ask around first before you do, some people can give you baby grains for free.
Any other questions, feel free to ask!