Right now there is no way to see stats of brothers unaffected by equipment.
To compare two fighters you have either to completely undress them (my 6 year old daughter even asked me “Why there are naked guys in your team?” once) or to do some cumbersome calculations.
It would quite useful to show base values in popups when you hover mouse over stats.
It would be even more useful to see there all calculated modifiers and what piece of equipment cause it but probably it is just too much to ask.