Brother Xavier is a bit weird. Why would I want +1 in a Guardian card in my Ally slot? And he can soak up other investigator's damage. And if he's discarded he does damage, a bit like a Beat Cop (0)? What kind of strange combination is this?

Yet the thing is ... he's really good. That +1 helps an investigator like Roland or Skids avoid sanity damage from the encounter deck. 3 health / 3 sanity is awesome, and he can tank for anyone in his location. And should things get desperate, and you find yourself in combat, he can use all his health and sanity and then do a meaningful amount of damage to get you out of trouble. In short, he's awesome.

I think Brother Xavier is actually better than Beat Cop (2); only slightly more expensive, cheaper in terms of XP, and can do as much damage. Beat Cop only wins if you really need that +1 combat, and can live without that extra sanity and willpower...

One of my most memorable plays with Brother Xavier was at the end of Dunwich Legacy, where I was facing a big 5 health enemy, and had Brother Xavier in play.

I played upgraded Dynamite Blast, which put 3 damage on me (well, on Brother Xavier) and then 3 plus 2 on the enemy. Not that memorable in terms of fluking a lucky draw from the chaos bag, but testless 5 damage in a single action was incredible.

No, what made it memorable was thematically I think we can all work out what Brother Xavier did. What a noble sacrifice.

The soak ally. He soaks for you, he soaks for others. The willpower doesn't hurt, but he's honestly too expensive for that and the ally slot without charisma too valuable. You should try Police Badge and Bandolier before playing xavier for the +1

If you want to aggressively keep the map free from enemies, you should look for allies in the local police station.

As a defensive card in a slot important for the offensive, he is probably preferred over Beat Cop(2) only by Diana Stanley and Carolyn Fern, who likely do not want the +1.