What kind of trouble can I get into if I do not make an elderly person take a shower?

Get him caregiver who will help him shower or do bed bath. He might be afraid of falling. Hugs 🤗

Many of us are unrealistic about how often showers and hairwashes are actually required. If he doesn’t smell, whatever he is doing is OK. If he does smell, check how often he is changing his clothes – he may be skipping it to avoid ‘being a trouble’ if you do the washing. Make sure he has clean clothes to put on after whatever sort of wash he does. If he still smells, it’s not OK to share your place, and he needs an ultimatum. But please check all the other advice too – the energy required to strip, shower, dry and dress can feel like a workout at the gym, and it’s heaps worse if you don’t feel safe on your feet.

One other option might be to hire a male carer just to help him wash. If you’ve done all these things, I can’t see that you are at any risk yourselves.

The man can choose to shower or not. Unless you are his paid caregiver you have no duty of care.

However, it is reasonable to expect guests to be hygienic in your home. If his body odour is offensive, you can make the suggestionion for the comfort of everyone else. An awkward conversation, so be tactful if you can. Ask if the shower suits him? There may be a reason he feels unsafe (no grab bar) or he sits in a shower chair at home, or he prefers to wash at the sink. If you find out his preferences/needs you may have success.

Or he may just be a smelly old guy who doesn't care & refuses. If so - make the visit short!

I can see where OP might be worried about an appearance of neglect if elder is not showering. Sometimes outside observers think they see something wrong and report it - not realizing that it's elder refusing to shower and it's not that elder is being denied the opportunity to shower. I agree with trying the no rinse options. They do work. Another thought I had was to assess why he's refusing to shower. A lot of times they are afraid of falling, but don't necessarily want to say so or don't really understand it themselves. Finally, was he always this way? My elder was generally an unclean person way before I started providing care and I had to repeatedly explain that to people. It's just how it was. However, if a lack of cleanliness is a change in behavior for your friend's dad, then maybe it warrants a call to the doctor?

You really can't get into any trouble if he doesn't want to shower, however it is yours and your friends house, so you can lay down some ground rules for living in your house, because who wants a stinky adult living with them? So you tell him that if he wants to continue to live there, he MUST take a shower at least once a week, and use the body wipes on the days he doesn't. And just make sure that you are willing to stand behind these rules, in case he decides not to obey them. Then you must insist that he finds somewhere else to live. Good luck.

Trampus, explore using no rinse products:  no rinse shampoo and no rinse soap.   Showers are unnecessary with those, and I've found they clean just as well as soap and water.   There isn't that fresh sense of a shower pouring down on you, but they're effective.

Maybe your friend's father needs to have a come to reality talk: he needs to assist in staying clean or consider finding someplace else.   Tough love can hurt, but it can also help, and stop the worrying that you'll get in trouble.