Foredom flex shaft setups are considered to be professional or industrial quality tools fir frequent use. Dremel doesn't really have the same reputation. The Foredom setups are also highly customizeable.
Foredoom manufactures three different speed motors. The Foredom SR 1/6hp motors which operate at a maximum 18,000 rpm which is slightly less than the 23,000 rpm the Dremel Fortiflex flex shaft tool operates at, there Are also the TX 1/3 hp Foredom motors which operate at a maximum 15,000 rpm, and the TX series motors which have a lower 5,000 rpm speed for low speed high torque.
The Foredom motors are available in both a hanging configuration, as well as a bench mount swivel configuration. The speed control can be done either with a foot pedal, or Separate dial module, or with the dial control mounted in the swivel mount.
The flex shaft part of the Foredom tools is also available in keyed, slip joint, or heavy duty square drive options. The shafts for the Foredom tools are also available in extra long 66" lengths.
Foredom also makes a number if different handpieces to use with the different shafts, although some of the handpieces are shaft type specific.
It may be possible to use the Forefom shafts and accessories with the Dremrl Fortiflex motor, but I'm not certain. Once you add in the cost of the shafts and handpieces the cost would be similar to that of a Foredom kit. A basic Foredom kit can probably slso be found for a similar price of a Dremel Fortiflex kit. Foredom also offeres a huge variety of sets eith most of the options pre assembled. The only drawback is the cost.
Alternately, if your father already has a dremel tool, a dremel flex shaft kit adapter with the flex shaft and some bits is about $50 to $60 if you're unsure your father would like it, and there are aftermarket foot pedal speed controllers the Dremel could be plugged into.
https://www.amazon.com/gp/aw/d/B01M...flex+shaft&dpPl=1&dpID=51XJNR+TRkL&ref=plSrch
https://www.amazon.com/dp/B000VV4SDS/?tag=atomicindus08-20
Foredom makes dedicated woodcarving kits for either chisel carving, or rotary carving.
http://www.foredom.net/woodcarvingkits.aspx