Stamos vowed to be “be by your side through it all.”

John Stamosis showing some brotherly love to hisFull HousecostarDave Coulier.

“My brother from day 1.

Dave Coulier and John Stamos

Dave Coulier and John Stamos in 2017.Kelly Lee Barrett/Getty

Kelly Lee Barrett/Getty

Coulier detailed the diagnosis and current treatment process in an interview withPEOPLE.

When that swelling proceeded to grow to the size of a golf ball, he visited the doctor.

This has been a really fast roller coaster ride of a journey.”

Los Angeles, CA - 1988: (L-R) John Stamos, Bob Saget, Dave Coulier appearing in the ABC tv series ‘Full House’, episode ‘Cutting It Close’.

Dave Coulier, Bob Saget, and John Stamos on ‘Full House’ in 1988.abc/getty

Stamos and Coulier starred alongside each other onFull Housefor nine years.

Much of the cast has remained close since, especially following Saget’sdeathin 2022.

Coulier noted to PEOPLE that Bring has been instrumental in his treatment process.

And they had a very specific plan for how they were going to treat this."

Another point of hope for Coulier is the child his own son Luc has on the way.

The baby, due in March, willmake Coulier a grandfatherfor the first time.