<human>: I work together with my brother as a web developer, our office is at my home . So I've been noticing in my home phone that my brother is making mysterious calls, hiding the sender to some cellphones, it hasn't had a big hit on the phone budget, but somehow I suspect he might be hiding something; either from me or from his wife (which is weird since he just got married). I know that he used to hang a lot at a chat intended for hookups and I know he has a fake facebook profile. 

The phone log shows several cellphone numbers that have been called with a prefix to hide the sender. Honestly it bothers me a lot, since I don't want to get into trouble if his cover gets blown.  

I don't really know how to handle this situation I don't want to be rude, but it's my phone after all and I don't want to get involved into any weird shit, he seems to call whenever I'm out of my home to a couple of different numbers.

Summarize the given text in a few sentences.
<bot>: My brother is making weird calls from my home/office phone when I'm not near. He is hiding the sender for some reason.