Experience with dry mouth and taking trhexyphen for tremors.

going to switch topics for as I am usually posting about my NM. My husband will be 75 soon and over the last several years has developed a tremor in this left hand. He is now going to a neurologists and he has prescribed trhexyphen 2mg four times a day. Almost from the beginning he started having dry mouth and a sore throat. Oh he also had thrush mouth but that seems to be gone but the sore throat and dry mouth are not. I also have seen changes in his behavior almost like maybe early stages of dementia but now I am worndering if this could be from the drug We see his dr sept 4th and hope to get some answers. Anyone out there have or know some one on this drug.. Thanks in advice