Help black smoke contained by house mystery? My mum has a mystery she keep finding black smoke in her...

My mum has a mystery she keep finding black smoke in her house.
She cleaned the window and the next afternoon they are dirty (inside) she had wash her curtains in living room and the following year the pattern partly way up from bottom be covered in black. She even woke up near black dust around her nose and when she blew her snout it was full of dust. She lives surrounded by a bungalow. She has have a sore throat and bad headache when she wakes up. she have a gas fire that has single been used once the boiler have not been serviced for 3 years and she have booked someone to look at it. Does anyone have any thought what this could be?
Could you please suggest the best stove?
Answers:    Turn OFF all gas appliances and ring the Gas board NOW. If there are sooty deposits coming from any the fire or boiler your mum could be dead tonight from Carbon Monoxide poisoning !!!! Headaches, flu approaching symptoms are the most common effect of this. DONT pocket chances - do it NOW xxx
Is this quote to remodel my kitchen modest?
You really entail to get a qualified gas get round as an emergency. ASAP.