Not long ago my older rat (5 months old) had a head tilt..
It was really scary to watch him trying to move. " Move" actually is not the right word. He was crawling and kept turning around. He could not balance at all no matter the kind of a surface he was on.
When I saw him like that, I instantly thought of a brain ataxy.
The following day I took him to the vet.
She "assumed" he had an ear infection, but was really trying to "talk me into" brain ataxy, cancer.. whatever bad you can think of....

What a cruel world of commerce..
Long story short...I was giving him the antibiotics (prescribed by the vet), and they did not seem to be working. So, on the weekend I visited one of the pet stores where I bought an ear cleancer for ferrets and started cleaning my rat's both ears with it. Guess what.. he is running around like a headless chicken..everywhere..
The moral of the story is:
No matter how bad a problem can look, the solution to it may be quite simple!
Good luck!