Mohammed and his wife would wish to manage the stoma by handling it with their left hand if possible - since the left hand is for unclean things and the right is for eating.
They do all have the same prohibitions in their diets, no pork, no alcohol (but as has been said before, some Muslims will be more exemplary than others, one size will not fit all!) A Muslim likes to wash himself in running water after going to the toilet, you will often find a jug of water by the loo for this purpose - so fresh water for washing the stoma area will be appreciated.
Please be aware though that different people will follow their religious guidances in different ways, and will do whatever is practical to keep themselves clean.
Ceremonial washing before the five daily prayers is essential to a practising Muslim, one cannot pray if one's body or clothing is soiled.