Would you risk being around infected person?

Ok ladies I would really appreciate your advice. This weekend is my mums bday celebrations. I'm spending the whole weekend with her and family. Only thing is, she has been signed off work for 5 weeks with a 'virus' that the doctors have not yet identified. Her symptoms are that its effected the nerves down one aide of her body and her face and arms and leg sometimes go numb. She has also had extreme fatigue. She needs to lie down after just a 20 min walk. They hae just signed her off for another month. 
I am worried that I might catch something and it could cause some harm / miscarriage. She has had it for five weeks and seen people and no one has got infected. And her Dr said its almost certainly not contagious. My question is - would you take the risk? I'd really appreciate some honest answers. My midwife said that pregnant women have very low immune systems and to stay away from ill people. I'm mostly worried because they just don't know what's causing it. If it were a common flu like virus I wouldn't be as worried. Thoughts? I don't want to upset my mum but I would obviously never forgive myself if anything happened an I would be devestated.