Sounds like there are two things going on here. First, his penis may be keratinized and he has lost a lot of sensitivity. He may be unaware of his loss. I know I was unaware before I started restoring.

Second, his skin bridges may or may not be irritating to him. The skin bridges do give you an opportunity to talk to him about this.  For example, when you are playing with him, you could ask him about his skin bridges. Ask him if they hurt or bother him. His reaction will tell you how receptive he may be talking about it and learning more.

I think most guys would appreciate having a partner pay attention to their body and ask questions. Be tactful and remember that many guys think highly of their penis. Also, depending upon how he is, maybe all you need to do is plant the seed and he will investigate for himself.