What Should I Do with My Indoor/Outdoor Cat While Abroad?

I have a ginger cat who is very attached to me. He always follows me around the house and garden, sits close to me, and waits for me to go to bed. He was an indoor cat for years when we lived in the city, but now that we’re in a village, he loves spending his days outside. However, he always comes back in the evenings to sit and sleep with me.

In a few months, we’re going abroad for 2-3 months. I have a friend who lives nearby who can stop by daily or twice a day, but I’m concerned. If I leave him indoors the entire time, he’ll be very unhappy and probably nag my friend every time they come over. But if my friend lets him in and out, I’m afraid he might feel abandoned after a while and stop coming back home.

I also have two more indoor/outdoor cats, but they’ll likely be fine with whatever I decide. What should I do?