Keeping two male Maremma Sheepdogs together

Hi everyone, I hope I’m posting this in the right section, but I’m looking for some advice. I have a 16-month-old male Maremma Sheepdog who lives in his own garden area of about 40 square metres. In the evenings, he leaves this space to spend 1-2 hours in a larger area. He’s a sweet, affectionate dog, though he can be very stubborn at times. For the last few days, I’ve been looking after a male Maremma puppy who is about 3 months old. As soon as the puppy arrived, we let them spend a few minutes together in the garden while we were there, and everything was fine. Since then, they’ve been spending time together in the larger space in the evenings and it seems to be going well. They play, sit close to each other, and chase one another... there hasn’t been a single growl. At night, when the big one goes back to his area, the little one sits right next to him, even though they’re separated by the mesh fencing. It’s as if the pup feels protected by the older dog during the night. I’m considering keeping him permanently so they can live together in this garden space... but unfortunately, I’ve only heard discouraging opinions about this. I’m asking if you could share any of your experiences, because I really don’t want to give the puppy up, but I also don’t want to make the wrong choice and compromise their well-being in the future. Just to clarify, the pup is currently living in the open countryside with his Maremma mum and a brother from a previous litter. Thanks to everyone who can spare a moment to help me make the right decision. Not just for my sake, but for theirs.