He did not pray in congregation because he was afraid that it would delay healing of his feet

Question

Praise be to Allah.

May Allaah
bless you for your eagerness to pray in congregation. I ask Allaah to make
us and you steadfast in obeying Him and to accept it from us and from you.

Yes,
sickness is one of the excuses for which one may stay away from prayer in
congregation.

It says in
al-Mawsoo’ah al-Fiqhiyyah (27/187):

This refers
to sickness which makes it difficult to go to the mosque in order to pray in
congregation.

Ibn
al-Mundhir said: I do not know of any difference of opinion among the
scholars concerning the fact that a sick person may stay away from prayer in
congregation because of his sickness. When the Prophet (peace and
blessings of Allaah be upon him) was sick he stayed away from the mosque and
said: “Tell Abu Bakr to lead the people in prayer.” End quote.

The fuqaha’
(may Allaah have mercy on them) have stated that if the sick person is
afraid that his recovery may be delayed, then he is excused and the duty of
worship is reduced in his case, whether it is prayer, fasting, purification
or anything else.

See:
al-Insaaf (2/305) and al-Mawsoo’ah al-Fiqhiyyah (14/258).

What counts
in such cases is the opinion of a trustworthy doctor, or knowledge of that
due to experience.

If a great
deal of walking will delay recovery, then there is no sin on you if you do
not attend prayers in congregation in the mosque. So long as you pray
regularly, you will have the reward of praying in congregation in sha
Allaah, because of the hadeeth of Abu Moosa al-Ash’ari (may Allaah be
pleased with him), according to which the Prophet (peace and blessings
of Allaah be upon him) said: “If a person falls sick or travels, there will
be recorded for him the same reward as that for what he did when he was
healthy or was at home.” Narrated by al-Bukhaari (2834).

And Allaah
knows best.