it looks a bit squashed in. Has it got room to grow? bearing in mind the conifer is growing as well.
were they made dead by weedkiller?
no way to fix it if the weeping branches have gone
The rootstock growth will be wild cherry and not what your MIL wants.
If the weeping branches are still there, be ruthless, cut off the upright ones
stem looks like a cherry?
Weeping trees are grafted. The rootstock is not a weeping tree. If shoots come from below the graft they will not be weeping and will also be much stronger growing than the weeping ones. They will win and the weeping branches will be overcome. Looks like that's what's happened here
it's unlikely to be the cause of problems.
I can't see what your tree is. The leaves I can see don't look sick. Have you a photo of the ones that look bad
that's lichen not fungus
I rarely get the scent of flowers but the leaves never fail.
any seed company, they all have a selection of colours every year
Not that rare. They grow in gardens all over, including mine.. Easy from seed.