you but someone else may benefit,,, old stone walls're usually mortar'd in place,,, soil acids attack mortar's lime which leaches OUT leaving the sand,,, this happens above ground AND below as well,,, repointing's always proper,,, HOWEVER, can't repoint wall's exterior w/o full excavation to the footer - you can't repair what you can't see,,, therefore the BEST method's to excavate the exterior & do the repairs correctly including toe drains, waterproofing membrane system, & protection board,,, yes, you can diy but your contractor'll have INSURANCE - you'd only have yourself to sue
most ' waterproofing ' companies'll try to resolve the problem by installing an interior ' water management system ' commonly mis-named a ' french drain ',,, as part of this system, a sump & pump'll be installed,,, i've heard of the 1 named as this was our work.
once owned an 1864 house in upstate ny w/laid stone fnd ( no mortar or full bsmt ), when the river was high, we got wtr in the small room ( 12 x 12 root cellar ) underneath,,, when the river was down, we didn't,,, old houses were never engineer'd or construct'd to have basements as ' living space ',,, nowadays, we think differently & try to re-engineer the original intent which's fine IF we invest enough to make it all work.
the guy's father in the above post must've been a retir'd electrical engineer
as no civil or structural engineer would ever have repair'd a crumbling wall like that & expected it to be permanent or structurally sufficient even tho it still may be working,,, utility poles were usually treated w/creosote, not tar, in vt,,, that would bring an environmental hazard into an habitable structure.