If we consider the idea of helium as a conjugate base, it has an electron pair so in theory it could act as a Lewis base if a sufficently strong Lewis acid was provided. It is important to undertsand that it is rather easy to form compounds of the heavy noble gases, the lone pairs on radon can bind to silver(I) ions to form complexes. This is the reason why a siliver exchanged zeolite is so good at adsorbing radon from air.
The problem is that the smaller size of helium than radon / xenon together with the higher electronegativity of helium will make it such a weak Lewis base.
We can regard Brosted acids such as acetic acid, hydrogen flouride and sulfuric acid to be Lewis acid/base complexes. The Lewis acid in question is the proton while the conjugate base is the Lewis base.
The great problem I see with cationic helium hydride is that we will be dealing with such a one sided covalent bond that it will not be very stable. Also it will tend to break down with great ease. If we construct the orbitial diagram for a hydrogen molecule we can see that HeH+ is isoelectronic with a hydrogen molecule. I predict that the difference in the energies of the atomic orbitials will be large and the bond energy for the He-H bond will be very low.
I think that while HeH+ is formally a Bronsted acid the synthesis of this acid will be difficult to say the least. I think that while this super acid might be "the super acid of super acids" it will be impossible to make in any large amount.
I think that almost any other atom will be able to displace the helium atom in something similar to a SN2 reaction. I think it is likely to be very unstable in condensed media.
There is a paper about the HeH cation, see Zhuan Liu and Paul B. Davies, J. Chem. Phys., 1997, 107, page 337. I will adding some more to the answer.