Honestly, if you’re in love with the house and you really want it, go for it, try to get them to cover as much as you can. At least you are somewhat aware of what you’re getting into, but beware these kinds of things have a tendency to balloon in costs. What starts out as 15k in estimated costs could easily end up being 25k by the time everything’s done.
If you’re not that attached to it if it’s “Just a house” to you, try to get them to cover the full cost of repairs, if they say no walk away. In the US price cuts have already started happening, houses are sitting on the market longer and longer again. On top of that, you said you’re buying for 85k + 15k for repairs that ends up being 100k and you can get a much better maintained house for 100k? I’d take that option if it were me and save myself the headache.