Underwear and accessories

My father's birthday is on 24 February 24 (1).

[ (1) The day comes after the month, at least in American English.]

I bought a (1) T-shirt for (2) his last birthday.

[(1) The "t" in "T-shirt" should technically be capitalized in writing. (2) "For" is the preposition used with events and holidays.  ex) for New Year's; for their anniversary; for my birthday.]

I will buy a watch for him for his (1) next birthday (2) because, (3) he has (4) bought a watch for himself, and I (5) liked it (6) very much (7).

[(1) Use of "for" with events and holidays.  (2) A sentence starting with "because" isn't complete if you only have one clause.  A complete sentence starting with "because" would be: "Because I took his watch, I will buy him another one for his next birthday." (3) You'd rarely use a comma after "because".  (4) Simple past works better here.  It is more conversational to use the simple past. (5) Always capitalize "I".  (6) The object of "like" must come directly after "like".  I changed "that watch" to "it" to avoid repeating the word "watch".  (7) How much you like something comes after what you like.  "Much" is never used by itself with "like".  You will always need "very". ]

Then I took (1)/ "borrowed" (2) this watch :)

[ (1) "Distrain" is never really used.  "Took" would probably be the simplest equivalent.  (2) You could also jokingly say that you borrowed it by using "".  For example, 'a "new" gadget' is understood to be the opposite because of the quotation marks.  But don't overuse this =)] 

Now, (1) I plan to buy a new expensive watch for my father.

[ (1) The comma after "now" is optional.  It can be there, but it would also be correct without it.]

He'll be very happy.

[Perfect! =)]

Good job! =)