<human>: Can you give me a shortened version of the text?

Hi there r/relationship_advice! I would like to preface in saying, I would rather not disclose the name of the instructor or the dojo, because if I turn out to be wrong I do not want to ruin this guy's reputation. 

Anyways on to my story. Five months ago I started looking around for a place for my son to take karate. I found a dojo in my small town and was told we could try it out. I let my ex (his dad) know and he jumped right on it. He takes him to karate every week, it is a fun bonding activity they do together. Because of my work schedule I can not attend very often. From the minute I saw the sensei there was something about him that rubbed me the wrong way. I could not put my finger on it, and it wasn't a "touch your kid" kind of creepy so I kept my mouth shut. However, lately I have had this overwhelming feeling that there is something wrong with this guy so I started to do some internet searching. The dojo has a little bio on this guy with a list of very admirable achievements, things that are very praise worthy. I can not find any record any where of these achievements outside of the dojo website. These are things that, without a doubt in my mind, could be found by some very simple google searching. My ex has developed a relationship with this guy and refuses to move my son dojos. I did not mention my concerns to him, just that 320$ a month for karate was way out of my budget. 

So I guess my question is, do I do anything? Do I keep my mouth shut? My son really enjoys karate and I want him to keep doing it but this seems very odd to me.
<bot>: my son's sensei has a laundry list of achievements I can find no record of anywhere except the dojo website.