Lot of medications have interactions which can cause troublesome side effects when taken together.
As your mother is taking anti hypertensive medications in the form of atenolol and irbesartan and cholesterol
lowering medication simvastatin
. No significant drug interaction
exists between these three regular medications.
As you are concerned about the potential drug interactions between the folic acid
and aspirin,again there is no clinically important drug interaction exists between these drugs.
You can continue with the above mentioned medications for your mother without worrying about drug interactions.