@jahncrish I see a lot of people on here saying formula before solids, and this is absolutely true and necessary. For children under 1 year old, solids are complementary, meaning the main purpose of them is to just introduce the baby to the idea of food, flavours and textures.
My baby will be 8 months old in a week, so this is his feeding schedule if you'd like to provide your mother with an outline. Keep in mind all babies babies eat different amounts suited to what they need.
8am - 6oz formula
9:30 - solids (usually baby cereal, 3oz)
12pm - 6oz formula
1:30 - solids (3oz)
3pm - 6oz formula
5pm - big solid dinner, usually 4-5 ounces
6pm - 4oz formula
8:30pm - I give him 6oz, he drinks what he wants, which can be anywhere between 3 ounces and the whole bottle. This is a top-up before bed to make sure he is full and has gotten all the calories he needs today.
In total, babies this age (and up to one year old) should have a minimum of 24oz of formula, up to 32oz in a 24 hour period (in Canada; the maximum varies based on where you live, up to 38oz I think).