I would enlist his father to do that.  I would think dad telling him it was a requirement with consequences if he did not comply should be enough to get him to improve his hygiene.  Then he would need to follow up.  Of course, if dad is not willing to insist on good hygiene, it's understandable why the kid has bad habits.

Enlist dad. I would refuse to let my kids have their gadgets or internet access if they did something like that. ‘No gadget till you have showered’

Also anti perspirant is a must for social situations such as school. 

my sons shower in the morning and spray antiperspirant, but even I notice that wearing off towards the end of the day and it can be really quite yukky. 

Enlist dad. I would refuse to let my kids have their gadgets or internet access if they did something like that. ‘No gadget till you have showered’

Also anti perspirant is a must for social situations such as school. 

my sons shower in the morning and spray antiperspirant, but even I notice that wearing off towards the end of the day and it can be really quite yukky. 

A 13 yo showering 4 times in 2 months is really gross.

But, this is his father's responsibility, not yours. What does he have to say about it?

You can not make the changes, your husband will have to enforce the change. If he is not interested in teaching his son all of these basic things, it will never happen. You will have to change the way you feel about it. 

I don’t say a word unless I cannot take the smell. And trust me I also know how long it’s been since they showered though I try not to pay attention  

It’s amazing how much these “parents” can ignore and then be surprised when it’s not happening. I got told by my DH that my son was just easier and liked being clean. I replied that he was easier now because I started him off as a toddler and trained him to be clean. 

Oh the bio mom and bio dad will make things change once cps comes knocking on the door., after school files a report to cps.

I agree that the bio parents need to deal with this. HOWEVER having a 19 yr old artistic SS who hates showers that lives with us, I can't always wait for his dad to be home to deal with showering.

I have found that really as bad as this sounds a little shame goes a long way. When I know he hasn't showered in a couple of days, because I can smell him, I call him out. I walk into the room, make a dramatic thing about sniffing " What is that smell?? SS seriously? You are stinking up the room! This is gross. Go shower now, you are making me want to vomit! You need to strip your bed too. You entire bedroom reeks of your stench!"

This usually will keep him showing for a month or so...

Try taking whatever he likes the most away. Favorite video game? Gone until he proves he can follow a schedule. Phone? gone. That should do it. That's how life works...you dont work? you dont get money. You dont get money? You cant afford things. It's the same with hygeine. If you dont shower you dont get to do  or have the things you want

Tell him he stinks. I have to tell all my boys to take showers and that they stink from time to time.  Boys are just gross.  SS13 used to stink really badly when he would come to us EOWE and his dad would tell him to go take a shower pronto and brush his teeth.  Since he's moved in with us a month and a half ago, I haven't noticed the BO anymore.  That leads me to believe his mom wasn't making him shower on a regular basis.  My bio boys all play sports so they super stink when they come home from practice/games.  They are made to shower before they eat dinner so the rest of us don't have to smell them.  Why does your DH not want you to address SS's hygiene? Is he afraid it'll hurt his feelings? How wil DH feel about SS's feelings when he goes to school and other kids start bullying him because of his smell?