Hi from the U.S.! That’s a tough one! What does he do if they nicely ask him to stop or is he past the point of understanding? (It sounds like, if he’s that advanced into dementia, that he will not understand.)
Honestly, my best recommendation is to get a male caregiver to do his ADLs.
If that is not possible, have two women assist with his ADLs. One woman holds his hands and talks to him gently while the other helps him get dressed, bathed, etc. He’ll feel comforted and, most importantly, he’ll have human contact, which is what he really wants and needs. Also, his hands will be busy! He won’t be able to touch anyone inappropriately while he’s holding hands with someone.