Wir pflegen den Patienten.

Because den Patienten is the direct object of the verb pflegen, so it is in the accusative case.

• der Patient = nominative singular, used for the subject
• den Patienten = accusative singular, used for the direct object

In this sentence:

• Wir = the subject, the people doing the action
• pflegen = the verb
• den Patienten = the person receiving the action

So German uses den, not der.

This is because der Patient is a weak masculine noun (sometimes called an n-noun).

These nouns add -en in most forms except the nominative singular.

So you get:

• nominative: der Patient
• accusative: den Patienten
• dative: dem Patienten
• genitive: des Patienten

This is very common with certain masculine nouns, especially words for people, such as:

• der Student → den Studenten
• der Kollege → den Kollegen
• der Mensch → den Menschen

So in your sentence, Patienten is not plural. It is still singular.

Because the subject is wir (we).

The present-tense forms of pflegen are:

• ich pflege
• du pflegst
• er/sie/es pflegt
• wir pflegen
• ihr pflegt
• sie/Sie pflegen

Since the sentence starts with Wir, the correct verb form is pflegen.

In this sentence, pflegen means something like:

• to care for
• to nurse
• to look after a patient

It often has a medical or caregiving sense when used with Patient.

Be aware that pflegen can also mean other things in different contexts, for example:

• einen Garten pflegen = to maintain a garden
• Kontakte pflegen = to maintain contacts
• eine Tradition pflegen = to preserve or cultivate a tradition

So the exact meaning depends on the object.

Yes. It uses the basic subject–verb–object pattern:

• Wir = subject
• pflegen = verb
• den Patienten = object

This is a very standard main-clause word order in German.

Also, in a normal German main clause, the conjugated verb is in the second position. Here that rule is followed:

1. Wir
2. pflegen

Yes. German present tense often covers both:

• We care for the patient
• We are caring for the patient

German does not usually need a separate form like English am/is/are doing.

So Wir pflegen den Patienten can describe:

• something happening right now, or
• something habitual or regular

The wider context tells you which meaning is intended.

Because Patient is a noun, and in German all nouns are capitalized.

So:

• der Patient
• ein Haus
• die Pflege
• der Arzt

This is one of the most noticeable spelling differences between German and English.

The pf at the beginning is a real consonant combination in German. English speakers often find it unusual.

A rough pronunciation is:

• pflegen ≈ PFLAY-gen

More exactly:

• pf = a quick p
  • f sound together
• e in the stressed syllable sounds like ay in many standard pronunciations
• g in -gen is pronounced as a hard g
• the final -en is a reduced ending, often like -en or -uhn

If saying pf together is hard at first, many learners start by exaggerating it:

• p...flegen

Then gradually make it smoother.

Yes, but it is not exactly the same in tone.

• Wir pflegen den Patienten = we are caring for / nursing the patient
• Wir kümmern uns um den Patienten = we are taking care of the patient / looking after the patient

pflegen often sounds more specifically connected to nursing, care, or professional caregiving.

sich um jemanden kümmern is broader and can mean taking care of someone in many situations, not only medical ones.

So both can work, but pflegen fits especially well when talking about patient care.

Here it is singular.

That can be confusing because Patienten can also be a plural form in other contexts.

In this sentence, you can tell it is singular because of the article den:

• den Patienten = accusative singular masculine
• die Patienten = nominative or accusative plural

So:

• Wir pflegen den Patienten. = We care for the patient.
• Wir pflegen die Patienten. = We care for the patients.

No. wir only means we.

The formal you in German is Sie, and it is capitalized.

So compare:

• Wir pflegen den Patienten. = We care for the patient.
• Sie pflegen den Patienten. = You care for the patient. (formal) or They care for the patient, depending on context

Capitalization helps:

• sie = they / she
• Sie = formal you

Because pflegen normally takes a direct object without a preposition.

So you simply say:

• jemanden pflegen = to care for someone

Not:

• für den Patienten pflegen
• um den Patienten pflegen

Some German verbs need prepositions, but pflegen does not in this meaning.

That is just something you learn with the verb:
pflegen + accusative object.