The two drivers have enjoyed an obviously very friendly relationship this year.
During the Azerbaijan GP, Stroll told the team that he wouldn't attack Alonso while running behind him, and the Spaniard later passed on brake balance information that he thought would help his team-mate.
Alonso made it clear that he's helping Stroll because he believes that he represents the long-term future of the team.
"We talk a lot during the weekend from Friday, already from Thursday, what we both felt here in the past, also in the strategy meeting, what we will do, what will be the plan for each of the cars and things like that," said Alonso when asked by Motorsport.com about his relationship with Stroll.
"So if we feel something in the car during the race that we didn't speak about, and there is something new that can help the other car, normally we communicate with the team.
"And yeah, it has been like this. I know that I will be in the sport for a few more years, but not many, and he will lead the team for the next 10 or 15 years. So I hope I can help Lance as much as I can in the next few years."
Asked if he had had that kind of relationship with a previous team-mate, he said: "Yeah, I had in the past, but only some of my radios were broadcast! But not this one. For whatever reason now F1 is kind to me."
Stroll said he was happy not to race Alonso in the early stages.
"We were both thinking about the long-term, the race, and he had better pace," he said. "I didn't want to push him in that sense.
"I felt like it was smart for both of us to manage at the beginning of the race. And then he kind of took off and had a really good pace on the hards, and I struggled with balance, and didn't really get into a happy place.
"I made that mistake in 16, when [Lewis] Hamilton got me, and then it felt like it was kind of just a bit tricky to the end of the race."
Regarding Alonso's brake balance message, he said: "I heard about that now! Yeah, he returned the favour! So, that was nice of him. I was told to think about brake balance and change a few things. So now I know it came from him."
Aston Martin team principal Mike Krack praised his drivers for working together so effectively.
"It's fantastic to see," said Krack. "It shows the maturity of Lance and Fernando, the way they work together, the way they also act with each other.
"They have clearly understood that our opponents are not the green car relative, but others.
"And I think if we can manage to keep this harmony between the two, pushing each other but also helping each other where it matters, it will only benefit us in the long run."
Asked if Alonso was acting like a big brother, he added: "Lance is not a little brother, they are both equal eye level.
"You have many times where Fernando looks at what Lance is doing and vice versa, so I think they are proper team-mates, not big brother and little brother. You can say older and younger perhaps."
Additional reporting by Jonathan Noble and Oleg Karpov
