It sounds like a classic scam unfortunately, lots of clues in the text such as ridiculously high salary, sob story, etc.
But the biggest clue of all is that this person is asking you to take the job without knowing you, without interviewing you, without checking if you'd be a good caretaker of the child
Keep away from anything like this, especially if it's unsolicited - these people are hardly worth the energy you need to press 'delete' :-)
Also, for a supposedly native English speaker, the English they've used is crap
I dont know if it scam please let me know if it is a scam!
I am Michael Phillips 47 Years Old, From United kingdom . I am an Estate Valuer in United Kingdom and I don’t usually stays home unless during weekends.I will like you to know that i have one kid which name is olive 3 years old. I want you to work for me as a nanny, who will be taking a good care of her because she is the only one left at home after her Mum died for two yrs now. I would be needing someone to take over from her in my absents. I need an aupair that is homely, caring; experienced that can take good care of my kid. I will put up a good offer of 600GBP per week to secure the services of you with good qualities to look after my kid, I will be very grateful if I can get a positive reply from you, and do not forget to give me your full details as soon as possible. God bless you