My brother and I digitised, retouched, and reprinted, some old family photographs, last year. Start from the highest non-interpolated resolution your scanner can provide.

I think the prints we started from were contacts made from large negatives, though the softness of the images suggested something more like a Box Brownie than a Agfa Billy Record in the optical stakes.

There's the potential for a quite good large print, but it may not stand up to a close look.

Anyway, the tiny picture is a same-size, partial, retouch of the worst part of your first picture.

It really needs a much bigger original, and a lot more care to get the shape of the nose right. It's lucky the other picture is good on the face.