When you have oil coming out of your breather tube it's caused by blow by of the oil.
Some amount of oil blow by is normal in the engine but excessive blow by can be caused by a few different things such as too much oil, bad pcv valve, clogged oil filter, worn piston rings etc.
Check your engine oil level to be sure it's not overfilled by a quart of oil or more.
If the oil is overfilled by a quart or more you need to drain the excess oil out to avoid damage to the engine.
If draining the oil doesn't fix the blow by then you might need a new PCV valve which are pretty cheap and usually easy to install.
And if that doesn't fix the problem then your engine may need rebuilt to fix blow by.
I have an old truck that I don't drive that often and it has excessive blow by but it's really just a farm truck so what I did was just put a oil jug in the engine bay near the radiator and then redirected a hose from the breather tube to the oil jug.
The excess oil gets into the jug and then when and if the oil gets a little low I just add the oil back into the engine.
So you could likely do the same thing if the engine isn't worth repairing or it's just an older vehicle that's not worth much.