Thanks Terpe! I tried to call the airline company, but the office is already closed in Manila. I'll try it again on Monday before she leaves for the airport, as her flight is Tuesday midnight. I actually emailed a letter in attention of the airline reception desk, which my mum will give when she checks-in explaining that my mum will be travelling alone for the first time, and that she would require assistance with her connecting flight to London Heathrow. I also stated in my letter that her hold luggage will be checked through to Belfast, so that my mum doesn't need to collect it in London Heathrow airport. I hope they'll give consideration to my mum, as I'm worried if she might miss her connecting flight. If only I have enough money to get home & travel with her...that I'll do.
I even have to choose the airline she has to travel with which specifically lands in Terminal 1 of LHR, as the flight to Belfast which is BMI is also on same terminal building & she doesn't have to get the airport bus just to get to the connecting flight. It's not cost effective, but it'll be easier for her, as time frame between two flights is on 2hrs.
I appreciate your advise...hope everything will go smoothly.