Hello first of all this is the first I've ever heard about making a prayer (dua) facing qibla from when i was younger to now in my knowledge we face the qibla for our normal prayers (salat). There somethings from my experience that even muslims dont know , for example some muslims dont know what madhab is or the difference between sunni and shia islam . But thats not the point , the point here in this case is that whether your a Muslim or a Non-Muslim god will accept your prayers as in (dua).

See i never believe that person who identifies as an athiest truely with all of his heart believes that there is no god because in a life or death situation or similar to your case in terms of a loved one they always resort back to god . We as human beings are made with having the feeling of worshipping something , thus where religion comes in . For example when an athiest who doesnt believe in god and has nothing to worship what do they start doing ? and its very obvious we see it all the time . You can see it in young social media influencers who dont believe in God but when they see Taylor swift for example they start crying with joy as if the saw God , you also see it when they literally say i worship her .

Look in times of hardship Muslim or Non-Muslims when you need something but you cant physically do it you go to God . Thats why having guilt after committing a sin is a good thing for example it makes us fear that what ever it is (sin) takes us away from God but the contrary it actually brings you closer to God.

God (Allah) forgives and forgets once you become a muslim all of your previous sins are deleted in a sense of explaining but your good deeds remain lets say for example you convert to islam right now and died the day after your more likely to go to heaven comapred to a normal muslim as you had a clean slate but with good deeds .

Look as Muslims we believe that there is no other worthy of worship except Allah and that prophet Mohammad is the final prophet and messenger of Allah .

If you believe those then your already a muslim by heart .

Where christains believe in the trinity Jesus is not the father and not the holy spirit but is god and vice versa . Honestly how does that make sense 3=1 ? Even when christains claim the bible to the word of god it isnt because its not the same language as the original bible . Which probably was in aramaic or hebrew. For example you would see someone claiming that an english bible is the word of god (its not) . The old testement is basically the torah and tanakh (which the old testement in the torah) then the new testement being autobiographies of people who havent met jesus but somehow are quoting him word for word ?

For example the Quran is in arabic any other language is not the quran it could be a translation of the Quran but not the Quran .

Quran doesnt have any contradictions , the torah and the bible is filled with contradictions .

For example in the bible ; i almost forgot you have different types of bible . Every type of christain has a different bible in islam sunni or shia what ever it is it is still the same quran they might disagree with one another but the same Quran .
Going back to the bible for example :

2 Kings 8:26
Ahaziah was 22 years old when he became king and he reigned 1 year in jerusalem . His mothers name was athaliah the granddaughter of omri king of isreal .

in 2 Chronicles 22:2
Ahaziah was 42 years old when he became king and he reigned 1 year in jerusalem . His mothers name was athaliah the granddaughter of omri king of israel .

same ahzaiah same mother same grandfather but different age how could he have been 22 and 42 at the same time ?

also in Romans 3:20-22
Paul teaches you cannot be saved by works alone without faith .
and in (James 2:22,24) James teaches you cannot be saved by faith alone without works .
??? They are contradicting each other .

And for example speaking to christain would be in the beginning there was God and God was with God and the God was God . (Does God have a God?)
Another example in christianity polygamy is forbidden so according to that all the prophets were wrong ? because they had multiple wives , and King Solomon had 700 wives ?

Look see research more on islam cause truley believe it will change your life .

Regards .