Does a 5 month old baby still root?

My mother in law was at my house last night and was holding my 5 month old son and he was getting sleepy and she was like awww look hes rooting at me. He hasnt been on the in about 2 months and he dont do it to me anymore. So when I went to get him so I could put him to bed she had a blanket over him so I took it off to pick him up and she had him squished up against her chest. I think she is just crazy (sometimes I think she thinks he is her own). Anyways my question is...does a month old baby still have the rooting reflex if he is not fed anymore?