My boyfriend (22M) keeps falling asleep whenever I'm with him.

I realize I might come across as insensitive for saying this, but here it goes. He’s on night shifts, which I totally get as I work late too, often until around midnight or 1 AM. I chose this schedule because my store is closed at night, and I thought it would align better with his sleep pattern. We agreed that it would help him stay awake, or at least be less overtired when he comes over to my place. Currently, we don’t have our own place, so I’m living with my parents. I can’t stay at his place anymore because I have an elderly cat who is very attached to me and refuses to eat unless I’m around. Whenever he visits, it feels like 80% of the time he’s either asleep or too worn out to engage with me. I struggle to empathize with this because I handle tiredness very well. I can easily pull an all-nighter and go to work and still seem fine, which I’ve done several times. I may feel a bit off, but I tend to act and perform just as usual. It’s frustrating because it feels like we hardly have any quality time together. I’ve brought this up with him several times, but the situation hasn’t improved. I know he can’t control falling asleep, so I try not to make a big deal out of it. What puzzles me is how he manages to stay awake at his home before and after work, yet appears unable to do so when he's at mine. At his place, he interacts normally with his family and is an engaging person, but when he’s with me, he seems less present, even when he’s awake. I've been hoping this would change for months. We had originally agreed he would stay awake when he came over, then sleep later after I went to bed, and keep that routine until his next work shift. However, he now just sleeps whenever he feels like it, while I’m usually wide awake. He’ll sleep at night when I sleep, nap in the morning when I’m up, and then again in the evening when I’m free. I don’t know how to help him; he apologizes for it, and I feel for him because it’s clear he’s exhausted, but it's really starting to wear on me.