Oh man. If you were 25 and he was 30 this would not be as much of a deal but I can see why he feels wierd about it. This is just an aspect of life. When your younger small age differences are more significant and more so if your living independently. Honestly even when your older its wierd with the parent child thing. It goes in reverse to. You have a single parent dating and the date spends the night and it can be wierd for the person not part of the household. I personally think you need to accept it and just see if he eventually gets to where he can manage doing it. I mean he is a guy so if the offer is on the table he will get around to mentioning it if he thinks he can handle it.