minimum required for a resident visa

Oh no I don't how is niarobi have u been

Yes, I've spent a week in Nairobi but not with these questions in my mind at that time.

Firstly, you should bear in mind that doing voluntary work without the correct (work) permit is not permitted, so you should be very careful, particularly around anything in the medical field.  The government do take this seriously.

If you want to set up your own business, you can do this, but for a permit which will allow you to work within your business and live in Kenya (Class G), one of there requirements is that you must have a minimum of $100,000 US to invest - a significant barrier for many.  Anything in the medical field will require additional registration.

A Class K permit would allow you to live in Kenya, but you can't do any paid work, or operate a business.  For that, you need an income from sources other than work of approx $24,000 US, or more per year.   

There isn't really an alternative, unless you happen to get married to a wealthy Kenyan.

Chiropractors are in Kenya.  There is a great practice in Nairobi, but I don't think that there is a practice in Thika. 

As for naturopathy/homeopathy, I think that you'd be wasting your time - people who are interested in natural medicine will go to their local herbalist, perhaps in their home village.  From experience, they have a considerable body of knowledge and some highly effective results. 

There are a few expats in Thika, many go to Thika Sports Club.

Thank you for this information, depressing though it is.
There must be some solution...

What kind of work permit are they looking for.  Can assist in processing one.

Thanks for the offer but I'm not looking for a work permit - I want to retire!