Brought a 13 year old dog home

So i had my dog since I was 11. I moved out of my moms house a year ago and she kept my dog. She’s moving to an apartment complex that don’t accept pets. But I have a house with a large backyard. So he’s moving back with me.

I have a 3 year old son and he’s known him since he’s been born. So how can I transition him to living here with me? I want him to sleep in the laundry room since it’s tile and it’ll be his own little space. He’s a buchón frise if that helps. Thank you !