I don't know about the beer but the sauna, or any hot/cold change in body temperature, is good for what ails.

Nature provides with a fever for a reason. Pathogens do not like high temperatures. I think it is a mistake to take medicine to lower fevers as long as they stay below about 101 or maybe 102. High fevers are dangerous and need to be dealt with (cool bath for example), but run of the mill fevers are the body's way of fighting infection. When we interfere with that by taking fever lowering drugs we reduce the ability of the body to deal with the pathogen.

My opinion, based on what I have read. No specific studies come to mind to back it up.