Putting money into house! Is it worth it now?

Last of the offspring has decided that he wants to move out of the family home, which is great news to my parents that have been waiting for the last few years to downsize, so now that he has left its now full-steam ahead!
But have they left it to late? They own a large detached 2 story house in a quite matured estate, but house & garden is quite dated, mum wants to put a few bob into doing it up but on the other hand my dad is saying she's wasting her time putting money in as anyone buying will rip everything back out and redo it to there own taste?
She also still has single pane glass windows and also thinking of replacing these before putting it up for sale thinking it will bring the value back up! So I really don't know who to agreed with my Dad who still wants near the price that he could have getting last year, or my Mum who is a bit more realistic in the price drop at the moment, but thinks that by throwing in a few quid and doing a quick job on the house will raise the price up again? I am at a lost with the 2 of them at the moment any advise would be great

there are certain things you can do that won't cost the earth to make the place more attractive
e.g.
Re-Paint the rooms
New light shades
Tidy the garden
Get rid of any clutter
Fix any leaky taps, broken latches, etc
clean everywhere thoroughly
new skirting boards
new bathroom tiles

You probably won't get the value of any major upgrades like double glazing, a new kitchen, a new bathroom, a landscaped garden, etc

Hi. I think there's a middle ground between your Mum and your Dad. He's right that any major spending (such as windows) would be a waste. However a good clean up taking out any very dated curtains, decor won't go amiss. IF they could get it together to paint the whole place magnolia and get cheapish plain carpets fitted - it would be probably a better investment. If it was me I'd seriously clean up (including grout in the bathroom!) and seriously de-clutter. Am thinking of upgrading my own place from the point of view of investment. Rang an auctioneer I knew today to ask him what sort of value putting in an ensuite would add to the house (it's a 4 bed semi with garage in the leafy south side!) and he told me €5,000. When I expressed disappointment, he told me that it would just sell much easier. Just a reminder, apart from all the stress involved of having workmen in the house, don't forget the mess they make. I'm a new member here - hope I'm not breaking any rules when I say that I wouldn't put a house on the market at the moment unless there was a very serious reason to move. Things are completely stagnant and I think it would be heartbreaking for them to have to try and sell in this atmosphere.