How To Do Wudu If You Can't Rinse Your Mouth
Rinsing mouth is not compulsory in normal wudu, so he can do wudu without it. In the matter of worship, the principle is of convenience. That is why Tayyamumm or dry ablution and running wet hand on socks is allowed. If a man is not able to perform wudu for any reason, or any part of his body, he can adopt dry ablution complete or only that part which is not supposed to wash.