I have a parrot, so know some general bird stuff...
I believe the calcium thing you are talking about is the cuttlebone, and yes, those are fine for the birds to have. The smaller birds seem to like them. I had one for my tiel when I had him.
Fresh seed and water at all times is a must. As for the sunlight, yes, he needs light, but I'd watch putting him directly in front of a window. Some of our windows get very hot direct sunlight mid-day and she wouldn't want the poor bird to be stuck in his cage, unable to get out of the direct sun while she's off at work or something. So I always make sure mine is not straight in front of the windows. Also there is the possibility of drafts in the winter.
Covering the cage at night is good, I do it for my bird too in order to "put him to bed".
Direct light.... yes birds need full spectrum lighting to grow feathers properly and to utilize some vitamins they have specific glands that can convert full spectrum lighting into usable vitamins. However, light through a window is filtered and thus is not full spectrum.... an OTT light is usually suggested and turned on a few hours a day.....
food.... birds need fresh water, fresh foods..... and a pelleted diet...... Harrisons is an excellent pelleted diet as is scenic (the one I use for my cockatoo) and lefabvres (or however you spell that) it is best to not use something that has colors..... Seeds are like candy and absolutely can be given but are not the best for an everyday diet as the birds will often choose what they like and don't like...... and thus it is not balanced..... my bhakti often has seeds and nuts but he always has a bowl of pellets as well.....
broccolli, spinach, carrots, bananas, apples, cantaloupe, berries, apples, are all excellent for birds.... i would never feed advocado as they are poisonous.......
parakeets do not need cuttlebones but most of them like them so they are fine. I would not use the grit covered paper perch covers as the glue on them is not good for a parakeet.....
Bird Respiratory systems are VERY SENSITIVE and odors tha twe don't even think about will often kill a bird..... I know a person who had a pine tree air freshener in her car and lost three quaker parakeets on the way to the vet due to the smell.......
NO CANDLES, NO INCENSE, NO PLUG INS, NO AIR FRESHENERS, NO TEFLON PANS, watch for new carpeting as it smells, watch when you buy new appliances as the wires and inside is often covered in teflon and creates a smell the first couple of uses..... anything that smells is potentially dangerous to a bird...... when I am doing things that can create fumes or odors I put bhakti upstairs into a room with an open window..... we are planning on getting a new stove but that won't be done until summer when I can put bhakti outside when we turn it on.
DO NOT EVER yell at a noisy bird.... it is reinforcing and will create further behavior problems...... there are many email lists on bird behavior... parakeets are little parrots.... they are no different and they can develop bratty behaviors as can any parrot..... an excellent book on behavior and such is Marty sue athans guide to a well behaved parrot..... there is another book called my parrot my friend but I like the first one better. Parakeets can be big honkin brats. no shooting him wiht a squirt bottle, no yelling no throwing things at him no banging the cage.... the best thing to do to extinguish bad behaviors or unwanted behaviors are to ignore him when he is being obnoxioius and rewarding the behaviors you want. Its very similar to dog training and child traiing.....
if she has specific questions I would be happy to help as I am sure beau will as well
good luck
s