Wslmz, ur daughter is an adult. 21 is certainly not a child anymore, she definitely knows by now what's right, & what's wrong.
U r right to b concerned, as her bf must respect her, & if he likes her dat much to buy her extravagent gifts & give her money, he needs to come and introduce himself to u and the grls father. And ask for a formal proposal.
Odawise, whose to know if he is just using her? Apart from that, a lot of barakah is lost in a persons life, if u choose to follow behaviours dat r not islamic.
I am not saying that ur daughter is doing anything wrong, am jus sayin, it is easy for a grl to fall hopelessly in love wit a guy, esp if he showers her wit affection, love and gifts.
Many grls mistake dis for true love.
Ur daughter must respect herself, and not accept money from boys, whether its her bf or not.
if the boy does not formally commit, or come home and introduce himself,at least
Express wot his intentions r, I'd b worried too.
As gifts of that sort are of a personal nature.
He probably will expect something in return, mayb her loyalty etc. Thus this will decrease her options, from maybe her actually meetin a decent boy or noticing the oda proposals as a potential.
This is not healthy, becos if her bf leaves her one day for sum1 else, mayb younger and more beautiful, wot position will dat leave her in?
Jus time wasted and alota heartache.
Talk to ur daughter, just the two of u, have a heart to heart wit her and voice ur concerns.
In da end, mothers only want what's best 4 their children.
The youth must b guided and u did the right thing by confronting her.
Even If she rebels, at the back of her mind, ur words will still b there, and she will ponder over them and maybe even start asking her bf y doesn't he come home to introduce himself
Etc.
u should also tell ur daughter dat u do trust her judgement,
Bt there r times when a mother needs to intervene, esp when she can clearly see something is not right.
May Allah make it easy for u, inshAllah ameen.