soften thick suede on a vintage coat?

Yes!

As long as leather is able to be hydrated, it can be soften-up to as soft as you wish.

This is done with Hydrator-3.3 >Fatliquor-5.0 system.

Hydrator-3.3 in this instance will relax and separates the stick together fiber prior to Fatliquor-5.0 replenishing it.

Hydrator-3.3 acts as a preconditioner while the fatliquor (fat, oil and water) does the function of softening the leather.

Fat plumps the leather with fullness.

Oil lubricates each fibrils so that they slide over one another smoothly like millions of well lubricated interlocking hinges.

Water that encase the fat and oil molecules, when breaks free during the ionic attraction takes places impart a breathing space for leather breathability or natural transpiration for wearing comfort.

Products information:

Leather Doctor Hydrator-3.3

Leather Doctor® Hydrator-3.3 is a waterbased pH 3.3 leather-safe hydrator. It is a fatliquor preconditioner with multi functional abilities. Surface application is primary to check for even surface tension free of blotchiness prior to fatliquor replenishing. Structural application will require saturating to an optimum level with moisture oozing out when gently pressed between thumb and fingers.
The multi functional abilities include:
a) to check for surface tension for an even appearance free from blotchiness prior to fatliquor replenishing.
b) To plumps, relaxes and separates crushed, shrunk and stick together fibrils for manipulating away-unwanted creases and wrinkles.
c) To rectify alkaline overexposure areas by facilitating colloidal water movement to redistribute the leather constituents from surrounding areas.
d) To activate the dormant dyestuff within the leather structure for color refreshing.
e) To facilitates colloidal water movement within the inter-fibrillary spaces for wicking foreign soiling particulates to resurface.
f) To stabilize, pH balance and charge the protein fiber below its iso-electric point (pI) ionic positive to hydrogen bond with the ionic negative fatliquor more effectively. This universal Hydrator-3.3 is for all leather types including pigmented, aniline, vachetta, nubuck, suede, hair-on-hide and woolskin.

Leather Doctor Fatliquor-5.0

Leather Doctor® Fatliquor-5.0, a micro emulsion of fat, oil and water is an anionic charged pH 5.0 fatliquor for rejuvenating all leather types. It relaxes coarse breaks, creases and wrinkles enhance suppleness and prevent cracking. It softens the leather with stretchability, compressibility and flexibility, while enhancing its rip tensile strength greatly. It is for replenishing the original fat and oil that diminishes thru sun-bleaching, ageing, heat and alkaline overexposure or cleaning. On application, the water-encased molecule breaks free when hydrogen bond attraction takes place between the fat and oil with the protein fiber. The excess free water content wicks out leaving a breathing space behind for leather natural transpiration. The fat plumps the leather with fullness from easily collapsing into creases and wrinkles during stress or flex, while the oil lubricates the fibers so that they slide over one another smoothly like millions of inter-connecting hinges. Thus helps to keep leather at its optimum physical performance and prevent premature ageing. This universal Fatliquor-5.0 is for all leather types including pigmented, aniline, vachetta, nubuck, suede, hair-on-hide and woolskin.